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  • 1. ArcGIS 9 ®Using ArcGIS 3D Analyst™ ®
  • 2. Copyright © 2000–2004 ESRIAll rights reserved.Printed in the United States of America.The information contained in this document is the exclusive property of ESRI. This work is protected under United States copyright law and otherinternational copyright treaties and conventions. No part of this work may be reproduced or transmitted in any form or by any means, electronic ormechanical, including photocopying and recording, or by any information storage or retrieval system, except as expressly permitted in writing by ESRI. Allrequests should be sent to Attention: Contracts Manager, ESRI, 380 New York Street, Redlands, CA 92373-8100, USA.The information contained in this document is subject to change without notice. DATA CREDITSExercise 1: Death Valley image data courtesy of National Aeronautics and Space Administration (NASA)/Jet Propulsion Laboratory (JPL)/Caltech.Exercise 2: San Gabriel Basin data courtesy of the San Gabriel Basin Water Quality Authority.Exercise 3: Belarus CS137 soil contamination and thyroid cancer data courtesy of the International Sakharov Environmental University.Exercise 4: Hidden River Cave data courtesy of the American Cave Conservation Association.Exercise 5: Elevation and image data courtesy of MassGIS, Commonwealth of Massachusetts Executive Office of Environmental Affairs.Exercise 6: Las Vegas Millennium Mosaic (Year 2000 Landsat) and QuickBird images data courtesy of DigitalGlobe.Exercise 7: Ozone concentration raster derived from data courtesy of the California Air Resources Board, Southern California Millennium Mosaic (Year2000 Landsat) image courtesy of DigitalGlobe, Angelus Oaks imagery courtesy of AirPhoto USA, Southwestern U.S. elevation data derived from U.S.National Elevation Data courtesy of the U.S. Geological Survey. CONTRIBUTING WRITERS Steve Bratt, Bob Booth U.S. GOVERNMENT RESTRICTED/LIMITED RIGHTSAny software, documentation, and/or data delivered hereunder is subject to the terms of the License Agreement. In no event shall the U.S. Governmentacquire greater than RESTRICTED/LIMITED RIGHTS. At a minimum, use, duplication, or disclosure by the U.S. Government is subject to restrictions asset forth in FAR §52.227-14 Alternates I, II, and III (JUN 1987); FAR §52.227-19 (JUN 1987) and/or FAR §12.211/12.212 (Commercial Technical Data/Computer Software); and DFARS §252.227-7015 (NOV 1995) (Technical Data) and/or DFARS §227.7202 (Computer Software), as applicable. Contractor/Manufacturer is ESRI, 380 New York Street, Redlands, CA 92373-8100, USA.ESRI, the ESRI globe logo, 3D Analyst, ArcInfo, ArcCatalog, ArcMap, ArcScene, ArcGIS, GIS by ESRI, ArcGlobe, ArcEditor, ArcView, the ArcGIS logo, are trademarks, registered trademarks, or service marks of ESRI in the United States, the European Community, or certain otherjurisdictions.Portions of this software are under license from GeoFusion, Inc. Copyright © 2002, GeoFusion, Inc. All rights reserved.Other companies and products mentioned herein are trademarks or registered trademarks of their respective trademark owners.
  • 3. Contents Using ArcGIS 3D Analyst 1 1 Introducing ArcGIS 3D Analyst 3 What can you do with 3D Analyst? 5 Tips on learning 3D Analyst 8 2 Quick-start tutorial 9 Copying the tutorial data 10 Exercise 1: Draping an image over a terrain surface 12 Exercise 2: Visualizing contamination in an aquifer 22 Exercise 3: Visualizing soil contamination and thyroid cancer rates 27 Exercise 4: Building a TIN to represent terrain 37 Exercise 5: Working with animations in ArcScene 51 Exercise 6: ArcGlobe basics 58 Exercise 7: ArcGlobe layer classification 68 3 Creating surface models 77 What are surfaces and surface models? 78 Creating raster surfaces from points 80 Interpolating a raster surface 89 Kriging interpolation 93 Saving all rasters in a specified location 96 Setting an analysis mask 97 Setting the coordinate system for your analysis results 98 Setting the output extent 99 Setting the output cell size 100 Creating TIN surfaces from vector data 101 Building a TIN 103 Creating a TIN from a raster 105 Creating a raster from a TIN 106 iii
  • 4. 12 4 Managing 3D data 107 ArcCatalog basics 108 Previewing 3D data 111 The camera, the observer, and the target 113 Displaying 2D data in 3D 117 Starting ArcScene from ArcCatalog 121 Creating a new 3D feature class 122 5 Displaying surfaces 123 Displaying raster surfaces in 3D 124 Displaying raster surfaces 125 Symbolizing areas with unknown values 132 Displaying TIN surfaces 133 Making a layer transparent 143 Shading a layer 144 6 Analyzing surfaces 145 Querying surface values 146 Understanding the shape of a surface 148 Calculating slope 150 Deriving slope from a raster surface 151 Calculating aspect 152 Deriving aspect from a raster surface 153 Mapping contours 154 Deriving contour lines from a surface 156 Analyzing visibility 158 Creating a line of sight 160 Deriving a viewshed 161 Computing hillshade 162 Deriving hillshade from a surface 163 Shading 3D surfaces in a scene 165 Determining height along a profile 166iv USING ARCGIS 3D ANALYST
  • 5. Finding the steepest path 167 Calculating area and volume 168 Reclassifying data 169 Reclassifying your data 170 Converting rasters and TINs to vector data 174 Converting surfaces to vector data 175 Creating 3D features 177 7 3D visualization 181 Creating a new scene 182 Adding 3D graphics to a scene 184 Feature data and 3D 185 Defining the z-values for a layer 186 Raster data and 3D 193 Defining the 3D properties of a raster layer 194 Converting z-units to x,y units 196 Offsetting the heights in a layer 197 Controlling when a layer is rendered 198 Using the 3D Effects toolbar 200 Using face culling to control the way layers are drawn 202 Changing a layer’s drawing priority 203 Viewing a scene from different angles 204 Managing scene viewers 205 Changing the viewer settings 207 Navigating through a scene using the Fly tool 210 Setting bookmarks 211 Viewing in Stereo mode 212 Setting the properties of a scene 216 Changing the vertical exaggeration 217 Using animated rotation 218 Changing the background color 220CONTENTS v
  • 6. Changing the scene illumination 222 Changing the scene extent 225 Changing the scene coordinate system 227 Selecting features in a scene 229 Exporting a scene 233 Printing a scene 235 8 Animation 237 3D animation 238 Creating animations 240 Capturing perspective views 241 Recording and playing back animation tracks 242 Creating keyframes 243 Making group animations 246 Making animations from paths 247 Using the Animation Manager 249 Timing properties in the Animation Manager 251 Saving an animation 252 Sharing animations: Loading an ArcScene or ArcGlobe Animation file 254 9 3D symbology 257 What is a 3D symbol? 258 Using 3D symbols 260 Using 3D styles 261 Making 3D symbols 263 The 3D Symbol Property Editor 264 Altering the placement of a 3D symbol 265 Offsetting a 3D symbol 266 Scaling the size of 3D symbols 268 Using 3D styles to assign symbology 270 Symbolizing points with 3D symbols 272 Symbolizing lines with 3D symbols 275vi USING ARCGIS 3D ANALYST
  • 7. Symbolizing polygon fills with 3D symbols 278 Saving the current styles 280 Organizing 3D style contents 281 Creating and modifying 3D symbols and elements 283 10 3D graphics and text 285 The 3D Graphics toolbar 286 3D text 289 Changing properties of selected graphic elements 290 Changing defaults for the way graphics appear 291 Graphics layers 293 ArcGlobe 295 11 Introducing ArcGlobe 297 What can you do with ArcGlobe? 298 12 Using ArcGlobe 301 Types of data you can use with ArcGlobe 302 Default layers 303 User-defined default layers 304 System default layers 305 Creating a new globe 306 The ArcGlobe document 308 The ArcGlobe table of contents and layer types 309 Layer drawing order 312 Navigating in ArcGlobe 313 Using the camera target to simplify navigation 316 Zooming to a layer’s extent 318 Using the Walk tool 319 Globe layer properties 320CONTENTS vii
  • 8. Setting the visibility range of a layer 321 Reclassifying a layer 322 Draped layers 323 What is a floating layer? 324 Layer cache properties 326 Globe display layer properties 328 Rasterizing features 329 Feature properties 330 Scaling 3D symbols 331 See-through position 332 Globe properties 333 Background options 335 Illumination options 337 ArcGlobe application-level options 340 Setting the default view at full extent 341 Application-level cache options 342 Disk caches 343 Level of detail 344 Compression options 345 Lossy spatial compression 346 Elevation compression 347 Table of contents options 348 What is caching and how do I use it? 349 Glossary 353 Index 363viii USING ARCGIS 3D ANALYST
  • 9. Using ArcGIS 3D Analyst Section 1
  • 10. Introducing ArcGIS 3D AnalystIN THIS CHAPTER Welcome to ESRI® ArcGIS® 3D Analyst™, the three-dimensional (3D) 1 visualization and analysis extension. 3D Analyst adds two specialized 3D• What can you do with 3D Ana- viewing applications, ArcScene™ and ArcGlobe™, that extend the lyst? capabilities of ArcGIS Desktop and adds additional capabilities to• Tips on learning 3D Analyst ArcCatalog™ and ArcMap™. ArcScene lets you make perspective view scenes in which you can navigate and interact with your geographic information system (GIS) data. You can drape raster and vector data over surfaces and extrude features from vector data sources to create lines, walls, and solids. You can also use 3D Analyst tools in ArcScene to create and analyze surfaces. ArcGlobe provides real-time pan and zoom of very large (hundreds of gigabytes) of 3D raster, terrain, and vector datasets with no perceivable hesitation on standard computer hardware. This has been achieved by the introduction of a new approach for indexing and quickly retrieving data. ArcGlobe is discussed in detail in Section 2 of this book. ArcCatalog is extended by 3D Analyst so you can manage 3D data and create layers with 3D viewing properties. You can preview scenes and data in 3D in ArcCatalog using the same navigation tools you use in ArcScene. ArcMap is extended by 3D Analyst so you can create new surfaces from your GIS data as well as analyze surfaces, query attribute values at a location on a surface, and analyze the visibility of parts of a surface from 3
  • 11. different locations. You can also determine the surface areaand the volume above or below a surface and createprofiles along a 3D line on a surface.3D Analyst also lets you create 3D features from existingtwo-dimensional (2D) GIS data—or you can digitize new3D vector features and graphics in ArcMap using a surfaceto provide the z-values. 4 USING ARCGIS 3D ANALYST
  • 12. What can you do with 3D Analyst?3D Analyst provides you tools in ArcScene and ArcGlobe foranalysis and visualization of 3D data. It also extends ArcCatalogand ArcMap so you can more effectively manage your 3D GISdata and do 3D analysis and 3D feature editing in ArcMap. Viewing a scene from another perspective with another viewer You can change the properties of 3D layers to use shading or transparency, and you can change the properties of a 3D scene to3D view of raster and vector dataWhat can you do with ArcScene?ArcScene provides the interface for viewing multiple layers of 3Ddata for visualizing data, creating surfaces, and analyzingsurfaces.Visualizing data3D Analyst lets you drape images or vector data over surfacesand extrude vector features from a surface. You can view a scenefrom multiple viewpoints using different viewers. 3D view of utility poles and power linesINTRODUCING ARCGIS 3D ANALYST 5
  • 13. Exaggerating the vertical dimension of a scene Slope and aspect rendering of surfacesset the vertical exaggeration of terrain, the coordinate system and You can derive new rasters of slope and aspect from surfaceextent for the scene, and the illumination of the scene. models, create contours, and find the steepest paths on a surface.Creating surfacesThe 3D Analyst tools that are available in both ArcScene andArcMap allow you to create surface models from your GIS data.You can interpolate raster surfaces and create or add features totriangulated irregular network (TIN) surfaces. Contours and steepest paths You can also analyze the visibility between different locations on a surface; create rasters that show the level of illumination of a surface (given a sun altitude and direction); and reclassify raster data for display, analysis, or feature extraction purposes.TIN and raster surfacesAnalyzing surfaces What can you do with ArcGlobe?3D Analyst lets you interactively query the values in a raster See Section 2, ArcGlobe, for detailed information on ArcGlobesurface and the elevation, slope, and aspect of TINs. functionality. 6 USING ARCGIS 3D ANALYST
  • 14. Line of sight created on a TIN in ArcMap, displayed in ArcSceneWhat can you do with ArcMap? ArcCatalog lets you browse your data and create and preview layers in 3D.Installing 3D Analyst lets you add the 3D Analyst toolbar toArcMap, so you can do all of the surface creation and analysis What can you do with ArcCatalog?tasks in ArcMap that you can do in ArcScene. It also adds ArcCatalog is the ArcGIS application for managing your GIS data.several tools that only operate in ArcMap: a tool that lets you 3D Analyst lets you preview and navigate your 3D data. You can create GIS data layers and define their 3D viewing properties. You can also preview the scenes you’ve created in ArcScene. You can create metadata for your 3D GIS data including 3D thumbnails of scenes and data. You can create empty 3D feature classes or shapefiles in ArcCatalog that can then be populated by digitizing 3D features in ArcMap.3D line graphic created on a raster in ArcMap and a profile graph ofthe line.find lines of sight on a surface, three tools for digitizing 3Dfeatures and graphics using z-values from a surface, and a toolthat lets you create graphs of the profile (change in elevationover distance) along a 3D line. Navigate the 3D preview; identify features, raster cells, and TIN triangles.INTRODUCING ARCGIS 3D ANALYST 7
  • 15. Tips on learning 3D AnalystIf you’re new to GIS, take some time to familiarize yourself with include detailed information that you can read if you want to learnArcMap and ArcCatalog. The books Using ArcMap and Using more about the concepts behind the tasks. You can also refer toArcCatalog contain tutorials to show you how to make maps and the glossary in this book if you come across any unfamiliar terms.manage GIS data.Begin learning to use 3D Analyst and ArcGlobe in Chapter 2, Getting help on your computer‘Quick-start tutorial’, in this book. You’ll learn how to open a 3D In addition to this book, use the ArcGIS Desktop Help system toscene, add and query data in a 3D scene, create surfaces, and use learn how to use 3D Analyst and ArcGlobe. To learn how to useArcScene with ArcCatalog and ArcMap. You’ll also learn how to Help, see Using a globe, add data in a globe, and navigate in ArcGlobe. 3DAnalyst and ArcGlobe come with the data used in this tutorial, so Contacting ESRIyou can follow along step by step at your computer. You can alsoread the tutorial without using your computer. If you need to contact ESRI for technical support, refer to ‘Contacting Technical Support’ in the ‘Getting more help’ sectionFinding answers to questions of the ArcGIS Desktop Help system. You can also visit ESRI on the Web at and for moreLike most people, your goal is to complete your task while information on 3D Analyst, ArcGlobe, and ArcGIS.investing a minimum amount of time and effort in learning how touse the software. You want intuitive, easy-to-use software that ESRI education solutionsgives you immediate results without having to read pages andpages of documentation. However, when you do have a question, ESRI provides educational opportunities related to geographicyou want the answer quickly so that you can complete your task. information science, GIS applications, and technology. You canThat’s what this book is all about—getting you the answers you choose among instructor-led courses, Web-based courses, andneed, when you need them. self-study workbooks to find educational solutions that fit your learning style. For more information go toThe first section in this book describes how to display your data three dimensions, to create new surfaces from existing data,and to analyze three-dimensional surfaces. Section 2 describeshow to add and display your data in ArcGlobe and how tonavigate and interact with it. Although you can read this bookfrom start to finish, you’ll likely use it more as a reference. Whenyou want to know how to do a particular task, such as addingshading to a surface or switching the navigation mode from spaceflight mode to atmospheric flight mode, just look it up in the tableof contents or the index. You’ll find a concise, step-by-stepdescription of how to complete the task. Some chapters also 8 USING ARCGIS 3D ANALYST
  • 16. Quick-start tutorialIN THIS CHAPTER 2 The best way to learn 3D Analyst is to use it. In the exercises in this tutorial, you will:• Copying the tutorial data • Use ArcCatalog to find and preview 3D data.• Exercise 1: Draping an image over • Add data to ArcScene. a terrain surface • Set 3D properties for viewing data.• Exercise 2: Visualizing • Create new 3D feature data from 2D features and surfaces. contamination in an aquifer • Create new raster surface data from point data.• Exercise 3: Visualizing soil contamination and thyroid cancer • Build a TIN surface from existing feature data. rates • Make animations.• Exercise 4: Building a TIN to • Learn how to use ArcGlobe and manage its data content. represent terrain In order to use this tutorial, you need to have the 3D Analyst extension and ArcGIS installed and have the tutorial data installed on a local or• Exercise 5: Working with shared network drive on your system. Ask your system administrator for animations in ArcScene the correct path to the tutorial data if you do not find it at the default• Exercise 6: ArcGlobe basics installation path specified in the tutorial.• Exercise 7: ArcGlobe layer classifi- cation 9
  • 17. Copying the tutorial dataFirst you will copy the tutorial data to a local drive. You will 3. Right-click the 3DAnalyst folder and click Copy.use ArcCatalog to browse to and copy the data.1. Click Start, point to Programs, point to ArcGIS, and click ArcCatalog. 3 1 4. Right-click the local drive where you want to place the tutorial data and click Paste. ArcCatalog lets you find and manage your data. The left side of the ArcCatalog window is called the Catalog tree; it gives you a bird’s-eye view of how your data is organized and provides a hierarchical view of the geographic data in your folders. The right side of the Catalog window shows the contents of the selected 4 branch of the Catalog tree.2. Click in the Location combo box and type the path to the arcgisArcTutor folder on the drive where the tutorial data is installed. Press Enter. 2 The folder is copied to your local drive. Now you will make a folder connection to the 3DAnalyst folder in the The ArcTutor folder is now the selected branch of the Catalog tree. Catalog tree. You can see its contents in the Contents tab.10 USING ARCGIS 3D ANALYST
  • 18. 5. Click the 3DAnalyst folder on your local drive and drag it onto the top-level node, Catalog, of the Catalog tree. 5 There is now a folder connection in the Catalog for your local copy of the tutorial data.In the graphics illustrating this tutorial, the ArcCatalogoption to use a special folder icon for folders containing GISdata is turned on. That is why the folder GISdata, in thegraphic above, looks different from the other folders. Youcan turn this option on in ArcCatalog, in the Options dialogbox, on the General tab. ArcCatalog works faster when thisoption is turned off, so it is off by default.QUICK-START TUTORIAL 11
  • 19. Exercise 1: Draping an image over a terrain surfaceViewing a remotely sensed image draped over a terrain 2. Check 3D Analyst.surface can often lead to greater understanding of the 3 Click Close.patterns in the image and how they relate to the shape ofthe earth’s surface.Imagine that you’re a geologist studying Death Valley,California. You have collected a TIN that shows the terrain 2and a satellite radar image that shows the roughness of theland surface. The image is highly informative, but you canadd a dimension to your understanding by draping the imageover the terrain surface. Death Valley image data wassupplied courtesy of NASA/JPL/Caltech.Turning on the 3D Analyst extensionYou will need to enable the 3D Analyst extension.1. Click Tools and click Extensions. 3 Previewing 3D data in ArcCatalog Before you drape the image, you will browse to the terrain data and preview it in ArcCatalog. 1. Navigate to the 3DAnalyst folder connection in the Catalog tree. 112 USING ARCGIS 3D ANALYST
  • 20. 2. Double-click 3DAnalyst. 5. Click the Preview tab. You can preview your GIS data in3. Double-click Exercise1. ArcCatalog. With 3D Analyst installed, you can also preview some data in three dimensions. 2 6. Click the Preview dropdown arrow and click 3D View. 3 6 7. Right-click above the preview window and click 3D View Tools. You see a folder called Data and a TIN layer called Death Valley Terrain. A layer is a shortcut to geographic data. It also stores information about how the geographic data should be drawn on a map or in a 3D scene.4. Click Death Valley Terrain. 7 4 5 6QUICK-START TUTORIAL 13
  • 21. The preview becomes a 3D preview, and a new set of The data rotates around its center. The Navigate tool tools appears on the 3D View Tools toolbar. also allows you to zoom in and out and pan across the data, depending on the mouse button that you click while Navigate dragging in the 3D preview. 9. Right-click on the 3D preview and drag down. Zoom In/Out Pan The Navigate tool is active when you first preview data in 3D. You can see the names of tools by hovering the pointer over the tool. 9 The Navigate tool allows you to rotate 3D data and change the apparent viewer height by clicking and dragging left and right and up and down, respectively, in the 3D preview.8. Click on the 3D preview and drag to the right. The pointer changes to the Zoom In/Out pointer, and the view zooms in to the data. 10. Click the middle button—or both the right and left buttons if you have a two-button mouse—and drag to the right. 8 Q14 USING ARCGIS 3D ANALYST
  • 22. The pointer changes to the Pan pointer, and the view The view returns to the full extent of the data. pans across the data.11. Click the Identify button and click on the TIN. Identify The Identify Results window shows you the elevation, slope, and aspect of the surface at the point you clicked.12. Close the Identify Results window. E Now you’ve examined the surface data and begun to learn how to navigate in 3D. The next step is to start ArcScene and add your radar image to a new scene. Starting ArcScene and adding data ArcScene is the 3D viewer for 3D Analyst. Although you can preview 3D data in ArcCatalog, ArcScene allows you13. Click the Full Extent button. to build up complex scenes with multiple sources of data. 1. Click the ArcScene button on the 3D View Tools toolbar. R ArcSceneQUICK-START TUTORIAL 15
  • 23. ArcScene starts. Note that many of the tools on the ArcScene Standard toolbar are the same as the 3D navigation tools that you see in ArcCatalog. 3. Click the Add Data button on the ArcScene Standard toolbar. 32. Click the Death Valley Terrain layer in the Catalog tree and drag it onto the right-hand side of the ArcScene window, then release the mouse button. 4. Navigate to the Data folder for Exercise1. 2 4 The TIN is drawn in the new scene.16 USING ARCGIS 3D ANALYST
  • 24. 5. Click dvim3.TIF. 7. Uncheck the Death Valley Terrain layer.6. Click Add. 5 6 7 Now you can see the whole image. The black areas are The image is added to the scene. parts of the image that contain no data and are a result of previous processing to fit the image to the terrain. You have added the image to the scene. Now you will change the properties of the image layer so that the image will be draped over the terrain surface. Draping the image While the surface texture information shown in the image is a great source of information about the terrain, some relationships between the surface texture and the shape of The image is drawn on a plane, with a base elevation the terrain will be apparent when you drape the image over value of zero. You can see it above the Death Valley the terrain surface. In ArcScene, you can drape a layer— terrain surface where the terrain is below 0 meters containing a grid, image, or 2D features—over a surface (a elevation (sea level); it is hidden by the terrain surface grid or TIN) by assigning the base heights of the layer from everywhere else. the surface.QUICK-START TUTORIAL 17
  • 25. 1. Right-click dvim3.TIF in the ArcScene table of contents 3. Click the option to Obtain heights for layer from surface. and click Properties. Because the TIN is the only surface model in the scene, it appears in the surface dropdown list. 4. Click OK. 1 The layer Properties dialog box appears. You can change how a layer is drawn on a map or in a scene by setting its properties.2. Click the Base Heights tab. The image is draped over the terrain surface. Now you will be able to navigate around the image and see 2 the relationship between surface texture, as shown by the image colors, and the shape of the terrain. Exploring the image You will use the navigation tools on the ArcScene Tools 3 toolbar to explore the draped image. 1. Click the Zoom in button. 1 418 USING ARCGIS 3D ANALYST
  • 26. 2. Click and drag a rectangle around the middle of the 4. Click on the scene and slowly drag up and to the left. image. 4 2 The scene zooms to the middle part of the image. The scene rotates, and the view angle lowers, so it looks as though you are looking down the valley, past the higher land on the left side of the scene. Elevated, rocky area3. Click the Navigate button. 3 Alluvial fan FloodplainQUICK-START TUTORIAL 19
  • 27. The elevated land is visibly rougher terrain than the flat The Scene Properties dialog box lets you set properties valley bottom. The surface texture—and therefore the that are shared by all of the layers in the scene. These color, in the radar image—of this rocky area is different include the vertical exaggeration, the background (sky) than the fine sediment of the floodplain—the yellow and color, the coordinate system and extent of the data, and black region in the valley bottom. The rocky area is also the way that the scene is illuminated (the position of the a different texture from the gently sloping alluvial fan light source relative to the surface). that runs past it, down onto the valley floor. 2. Click the General tab.Draping the radar image over the terrain surface allows youto see the relationship between the general shape of the 2 3land surface and the texture of the rocks and sediment thatmake up the surface.Exaggerating the terrainThe valley is a broad area, relative to the height of theterrain, even though the mountains at the edge of the sceneare more than 2,000 meters above the valley floor. In orderto enhance the sense of depth in the scene, and to bring outsubtle features in the terrain, you will exaggerate the heightof the terrain.1. Right-click Scene layers in the table of contents and click Scene Properties. 1 4 3. Type “2” in the Vertical Exaggeration combo box. 4. Click OK. The apparent height of the terrain is now doubled.20 USING ARCGIS 3D ANALYST
  • 28. You can now clearly see how the alluvial fan spreads out onto the valley floor, between the larger rocky area at the center of the scene and the smaller rocky area in the foreground at the left side of the scene. 1 1. Click File and click Save As. 2You have added depth to the radar image, explored thegeneral relationship between the data in the image and theterrain data, and enhanced the scene so that you canperceive more subtle variations in the terrain. 4Now that you’ve built the scene, you will save it so that youcan explore it later if you choose. 3Saving the sceneScenes, also called Scene Documents, are like maps. They 2. Navigate to the Exercise1 folder.contain information about how the layers that are in thescene should be rendered and where the data is located. 3. Type “Deathvalley”. 4. Click Save. The scene will now be available for you to open later.QUICK-START TUTORIAL 21
  • 29. Exercise 2: Visualizing contamination in an aquiferImagine that you work for a water district. The district is 3. Click Groundwater.sxd.aware of some areas where volatile organic compounds(VOCs) have leaked over the years. Scientists from yourdepartment have mapped some plumes of VOCs in theaquifer, and you want to create a 3D scene to help officialsand the public visualize the extent of the problem. 3Some of the data for the scene has already been assembledin the Groundwater scene. You will modify the scene tobetter communicate the problem. 4VOC data was supplied courtesy of the San Gabriel BasinWater Quality Authority.Opening the Groundwater scene document 4. Click Open.This scene document contains a TIN that shows the shape The Groundwater scene opens. You can see the fourof the contaminant plume, a raster that shows the layers in the table of contents.concentration of the contaminant, and two shapefiles thatshow the locations of parcels and wells. You will drape the Showing the volume and intensity ofconcentration raster over the plume TIN, extrude the contaminationbuilding features and change their color, and extrude the You’ll drape the raster of VOC concentration over the TINwell features so that the wells that are most endangered by of the contaminant plume surface to show the volume andthe contamination may be more easily recognized. intensity of contamination in the aquifer.1. In ArcScene, click File, then click Open. 1. Right-click congrd and click Properties. 1 12. Navigate to the Exercise2 folder.22 USING ARCGIS 3D ANALYST
  • 30. 2. Click the Base Heights tab. 4 2 3 5 6 5. Click the Color Ramp dropdown arrow and click a red3. Click the dropdown arrow and click plume to get the color ramp for the raster. heights from the plume TIN. 6. Click OK. Now you will change the symbology of the raster to show the intensity of the contamination. 7. In the table of contents, uncheck plume.4. Click the Symbology tab. 7 Now it is possible to see the shape of the plume and its intensity in 3D.QUICK-START TUTORIAL 23
  • 31. Showing the relationship of the plume to wells You will display the well points as vertical lines equal to the depth of the well. This information is stored in theYou can see that some of the wells are within the area of WELL_DPTH field.the plume. However, it is difficult to see which wells aremost seriously affected because the contamination is more 4. Click WELL_DPTH.widespread but less concentrated at greater depths.You will extrude the well features based on their depthattribute in order to see which wells intersect the plume. 41. Right-click wells and click Properties. 12. Click the Extrusion tab. 5 2 5. Click OK. 6. Click the dropdown arrow to apply the extrusion expression by adding it to each feature’s base height. The well depths are expressed as negative values, so they’ll be extruded downward. 3 6 73. Click the Calculate Extrusion Expression button. 7. Click OK.24 USING ARCGIS 3D ANALYST
  • 32. You can see the places where the wells intersect, or are 5. Type “* 100”.close to, the plume. Now you will modify the scene to showthe priority of various facilities that have been targeted forcleanup.Showing the facilities with a high cleanup priority 4Analysts in your department have ranked the facilitiesaccording to the urgency of a cleanup at each location.You’ll extrude the facilities into 3D columns and color codethem to emphasize those with a higher priority for cleanup.1. Right-click facility and click Properties.2. Click the Extrusion tab. 6 6. Click OK. The expression you created appears in the Extrusion value or expression box.3. Click the Calculate Extrusion Expression button. 2 34. Click PRIORITY1.QUICK-START TUTORIAL 25
  • 33. 7. Click the Symbology tab. 11. Click the Save button.8. Click Quantities.9. Click the Value dropdown list and click PRIORITY1. W 8 7 9 Q10. Click OK. The facilities are now extruded in proportion to their priority score. The scene now shows the shape and intensity of the contamination, the wells in relationship to the plume, and the facilities that need to be cleaned up in order to prevent further pollution of the groundwater. Now you’ll save your changes to the scene.26 USING ARCGIS 3D ANALYST
  • 34. Exercise 3: Visualizing soil contamination and thyroid cancer ratesIn 1986, after the catastrophic accident at the Chernobylnuclear power plant in Ukraine, a large amount ofradioactive dust fell on Belarus. Since then, scientists havestudied the aftermath of the accident. One tool for exploring 2the data is 3D visualization. In this exercise, you will createtwo surfaces from point data collected in Belarus. One setof points contains measurements of soil CS137concentrations. CS137 is one of several radioactive isotopesreleased by the accident. The other set of points shows the 3rates of thyroid cancer, aggregated by district, with thesample point placed near the district centers.The CS137 contamination and thyroid cancer data was The CS137 soil measurements are shown with smallsupplied courtesy of the International Sakharov point symbols, using a graduated color ramp to show theEnvironmental University. intensity of the contamination. The districts’ thyroid cancer rates are shown with larger symbols, using aViewing the point data different color ramp.First, you will open the Chernobyl scene and view the point Creating 3D point featuresdata. The soil CS137 samples are 2D points with some attributes.1. Click File and click Open. One way to view 2D points in 3D is by setting an extrusion expression, or a base height. You can also incorporate a z-value into a feature’s geometry to allow it to be directly viewed in 3D without the need to set a base height from a 1 surface or an attribute. First, you’ll add the 3D Analyst toolbar to ArcScene.2. Navigate to Exercise3 and click Chernobyl.3. Click Open.QUICK-START TUTORIAL 27
  • 35. 1. Click View, point to Toolbars, and click 3D Analyst. 3. Click the Input Features dropdown list and click Subsample_1994_CS137. 3 4 1 5 The 3D Analyst toolbar in ArcScene contains several 3D analysis and data conversion tools. The ArcMap 3D Analyst toolbar contains the same tools, plus several 6 additional tools that you can use in ArcMap. Now you will create 3D point features from the soil 4. Click the Input Feature Attribute button, then click the CS137 points. Input Feature Attribute dropdown list and click CS137_CI_K.2. Click 3D Analyst, point to Convert, and click Features to 3D. 5. Change the output feature name to CS137_3D. 6. Click OK. The features are converted to 3D point features. However, they still seem to be resting on a flat plane because the CS137 concentration values range from 0 to 208.68, which is small relative to the horizontal extent of the data. 228 USING ARCGIS 3D ANALYST
  • 36. Increasing the vertical exaggeration 3. Click Calculate From Extent.You will exaggerate the scene to show the new points with 4. Click OK.their height embedded in the feature geometry. 5. Click the Full Extent button.1. Click View and click Scene Properties. 5 Now that you can see the new 3D points in the scene, you can turn off the original CS137 sample point layer. 6. Uncheck the box in the table of contents beside Subsample_1994_CS137 and click the minus sign beside 1 the box to hide the classification.2. Click the General tab. 6 2 Extruding columns Viewing points in 3D space is one way to investigate data. Another way is to extrude points into columns. You will 3 extrude the thyroid cancer points into columns to compare them to the contamination data. 1. Right-click ThyroidCancerRates and click Properties. 1 4QUICK-START TUTORIAL 29
  • 37. 2. Click the Extrusion tab. 6. Click OK on the Expression Builder dialog box. 7. Click OK on the Layer Properties dialog box. 2 Now the district centroid points are shown with columns proportionate to the thyroid cancer rates. If you navigate the scene you will see that the areas with the highest contamination levels also tend to have high thyroid 3 cancer rates, although there are areas with lower CS137 contamination levels that also have high cancer rates. Creating a surface from point sample data3. Click the Calculate Extrusion Expression button. You know what the soil concentrations of CS137 are at the4. Click INCID1000 (the rate of cases per 1,000 persons). sample point locations, but you do not know what they are at the locations between sample points. One way to derive the information for locations between sample points is to interpolate a raster surface from the point data. There are many ways to interpolate such surfaces, which result in 4 different models of varying accuracy. In this exercise you will interpolate a surface from the samples using the Inverse Distance Weighted (IDW) interpolation technique. 5 IDW interpolation calculates a value for each cell in the output raster from the values of the data points, with closer points given more influence and distant points less influence. 1. Click 3D Analyst, point to Interpolate to Raster, and click Inverse Distance Weighted. 6 Because the z-values of the phenomena that you are comparing have different ranges, you will multiply the cancer rate by 100 to bring the values into a range 1 similar to that of the CS137 measurements.5. Type “* 100”.30 USING ARCGIS 3D ANALYST
  • 38. 2. Click the Input points dropdown list and click 6. Click Save. Subsample_1994_CS137. 7. Click OK. 2 3 43. Click the Z value field dropdown list and click CS137_CI_K. 74. Click the Browse button.5. Navigate to the Exercise3 folder and type ArcScene interpolates the surface and adds it to the scene. “CS137_IDW” in the Name field. 6 5QUICK-START TUTORIAL 31
  • 39. Viewing the interpolated surface 4. Click the Base Heights tab.Now that the surface has been added to the scene, you cansee that there are two areas with very high concentrations 4of CS137. You will view the surface in perspective, with anew color ramp, to better see its shape.1. Right-click CS137_IDW and click Properties. 5 12. Click the Symbology tab. 2 6 5. Click Obtain heights for layer from surface. 6. Click OK. 7. Uncheck CS137_3D in the table of contents. 33. Click the Color Ramp dropdown arrow and click a new color ramp. 732 USING ARCGIS 3D ANALYST
  • 40. Now you can see the interpolated surface of CS137 1. Click Selection and click Select By Attributes. contamination, along with the thyroid cancer rate data. 1 2. Click the Layer dropdown arrow and click ThyroidCancerRates. Next, you will select the province centers with the highest rates of thyroid cancer. 2Selecting features by an attributeSometimes it is important to focus on a specific set of dataor specific features. You can select features in a scene bytheir location, by their attributes, or by clicking them withthe Select Features tool. You will select the provincecenters by attribute to find the locations with the highestrates. 3 3. Double-click INCID1000 in the Fields list.QUICK-START TUTORIAL 33
  • 41. 4. Click the >= button. 4 They are drawn in light blue to indicate that they are selected. Viewing the attributes of features 6 You will investigate attributes of the selected locations and find out how many cases of thyroid cancer occurred in these districts. 1. Right-click ThyroidCancerRates and click Open Attribute Table. 7 8 15. Type “0.5”.6. Check the selection expression you’ve built.7. Click Apply.8. Click Close. The province centers with thyroid cancer rates greater than 0.5 cases per 1,000 are now selected in the scene.34 USING ARCGIS 3D ANALYST
  • 42. 2. Click the Selected button. 4. Right-click CASES and click Statistics. 4 2 The table now shows only those features that you The total number of cases in the selected set of selected. 11 province centers is 176.3. Right-click CASES and click Sort Ascending. 5. Close the Selection Statistics dialog box. 3 5 The selected province centers are sorted according to the number of cases.QUICK-START TUTORIAL 35
  • 43. 6. Click the Navigate button and click on the scene. You can work in ArcScene while the attribute table is open.7. Click the Save button. 7In this exercise you have created 3D features, extrudedpoint features, and interpolated a raster surface from a setof data points. You’ve compared the extruded vector datato the surface data and explored the attributes of the vectordata.36 USING ARCGIS 3D ANALYST
  • 44. Exercise 4: Building a TIN to represent terrainThe town of Horse Cave, Kentucky, is situated above a 1. Click File and click Open.cave that once served as the source of drinking water andhydroelectric power for the town. Unfortunately, thegroundwater that flows in the cave was polluted byhousehold and industrial waste dumped on the surface and 1washed into sinkholes. Dye tracing studies and a three-dimensional survey of the cave revealed the relationshipbetween the cave passages and the town and demonstratedthe connection between open surface dump sites and 2. Navigate to the Exercise4 folder and double-clickcontamination of the groundwater in the cave below. BuildTIN.sxd.Thanks to the development in 1989 of a new regionalsewage facility and the joint efforts of the Cave ResearchFoundation and the American Cave ConservationAssociation (ACCA), the groundwater is cleaner, and thecave has been restored. It is now operated as a tour caveand educational site by the ACCA. 2Cave data was provided courtesy of the ACCA.Viewing the cave and the landscapeFirst you will open the BuildTIN scene and view the cavesurvey and some terrain data layers. You’ll use this terraindata to create a TIN and drape some other layers on it to The scene opens, and you can see the location of roadsvisualize the relationship of the cave to the town. and railroads, some sample elevation points, and a few significant contour lines. In the table of contents, you can see that some layers have been turned off.QUICK-START TUTORIAL 37
  • 45. 3. Check the box to show the Cavesurvey layer. 1. Click 3D Analyst, point to Create/Modify TIN, and click Create TIN From Features. 1 3 2. Check vipoints point. 4 24. Right-click Cavesurvey and click Zoom To Layer. The cave survey data consists of PolylineZ features, which are automatically drawn in 3D because they have z-values embedded in their geometry. They appear above the rest of the data because all of the other layers are drawn with the default elevation of 0. 3 In the next steps you will build a TIN to provide the base heights for the streets and a photo of the town. 4Creating a TIN from point data The SPOT field name appears in the Height sourceYou have a point layer called vipoints point. This coverage dropdown list, and the layer will be triangulated as massconsists of points with an attribute called SPOT that points.contains elevation values taken at these points. You’ll create 3. Change the default path so that the new TIN will bethe TIN surface model from these points. created in the Exercise 4Terraindata folder. 4. Click OK.38 USING ARCGIS 3D ANALYST
  • 46. The TIN is created and added to the scene. Note that it 1. Click 3D Analyst, point to Create/Modify TIN, and click is drawn above the Cavesurvey layer; the elevation Add Feature to TIN. values in the TIN define its base height. 1 2. Check railroad.While this TIN is a fairly good model of the surface, youcan make it more accurate by adding some more features.Adding features to a TINNow you will add hard and soft breaklines and a clip 2polygon to the TIN. You’ll add the railroad features as soft 3breaklines, so they’ll be represented on the surface but 4won’t influence the shape of the surface. You’ll add thebrklines features as hard breaklines with elevation values torefine the shape of the surface in areas that you’re mostinterested in. Finally, you will add the smclp polygon as a 3. Click the Height source dropdown arrow and clicksoft clip polygon to more smoothly define the edge of the <none>.TIN. 4. Click the Triangulate as dropdown arrow and click soft line.QUICK-START TUTORIAL 39
  • 47. 5. Check brklines. 7. Click the Height source dropdown arrow and click <none>. 8. Click the Tag value field dropdown arrow and click <none>. You have defined the feature layers that you want to add to your TIN and specified how they should be integrated into the triangulation. 5 The Add Features To TIN tool detects that there is an ELEVATION field and uses it for the height source. You will accept the default and triangulate them as hard 7 breaklines.6. Check smclp. 8 9 9. Click OK. 640 USING ARCGIS 3D ANALYST
  • 48. 2. Click the Base Heights tab. 3 2 The new features are added to the TIN. 4 You can see that the railroad follows a bed that has been leveled somewhat relative to the surface.Setting features’ base heights from the TINNow you will set the base heights for the road and railroadfeatures from the new TIN.1. Right-click roads and click Properties. 5 3. Click Obtain heights for layer from surface. 4. Click the dropdown arrow and click tin1. 5. Click OK. 1 The road features are now draped over the TIN surface that you created. Now you will drape the railroad features over the surface. 6. Right-click railroad and click Properties.QUICK-START TUTORIAL 41
  • 49. 7. Click Obtain heights for layer from surface. The railroad features are now draped over the TIN surface that you created. Next you’ll drape the aerial photo over the TIN. Setting raster base heights from the TIN Including the aerial photo of the town in the scene makes 6 the relationship between the cave and the town much more evident. You’ll drape the raster over the TIN and make it partly transparent so that you’ll be able to see the cave beneath the surface. 1. Right-click photo.tif and click Properties.8. Click OK. 7 1 842 USING ARCGIS 3D ANALYST
  • 50. 2. Click the Base Heights tab. 6. Type “30” in the Transparent text box. 7. Click OK. 3 2 8. Check photo.tif. Now the aerial photo is 30 percent transparent. You can see large patches of the TIN over the photo because the TIN and the photo have the same drawing priority. If you wanted the TIN to be visible below the photo, you could 4 change its drawing priority to 10 (lowest) on the Rendering tab of the TIN’s Layer Properties dialog box. You could also offset the base height of the TIN or the photo by a3. Click Obtain heights for layer from surface. small amount.4. Click the dropdown arrow and click tin1. Cleaning up the scene5. Click the Display tab. To clean up the scene you’ll turn off some layers that are no longer needed and make the cave line symbol larger. 6 5 1. Uncheck vipoints point. 2. Uncheck brklines. 3. Uncheck tin1. 4. Double-click the line symbol for the Cavesurvey layer. 1 2 4 3 7QUICK-START TUTORIAL 43
  • 51. 5. Type “5” in the Width box. 1. Click the Launch ArcMap button. 1 ArcMap starts. 2. Click OK. 5 66. Click OK. Now you can see the three-dimensional passages of the cave, symbolized by thick lines. The surface features and the aerial photo provide context, so you can easily see the relationship of the cave to the town. 2Creating a profile of the terrainThe cave follows the valley floor orientation. To get an Now you will add the 3D Analyst toolbar to ArcMap. Theunderstanding of the shape of the valley, you will create a ArcMap 3D Analyst toolbar contains a few tools that do notprofile across the TIN. In order to create a profile, you appear on the ArcScene 3D Analyst toolbar. Two of thesemust first have a 3D line (feature or graphic). You will start are the Interpolate Line tool and the Create Profile GraphArcMap, copy the TIN to the map, and digitize a line to tool, which you will use to create your profile of themake your profile. surface.44 USING ARCGIS 3D ANALYST
  • 52. 3. Right-click on one of the ArcMap toolbars and click 5. Check 3D Analyst. 3D Analyst. 6. Click Close. 5 3 6 The 3D Analyst toolbar appears. The 3D Analyst extension is enabled.4. Click Tools and click Extensions. 7. In the ArcScene table of contents, right-click tin1 and click Copy. 7 4QUICK-START TUTORIAL 45
  • 53. 8. In the ArcMap table of contents, right-click Layers and 11. Click on the upper-left corner of the TIN, drag the line click Paste Layer(s). to the lower-right corner, and double-click to stop digitizing. W 89. In the ArcMap table of contents, check tin1. 9 You can create a profile along a line with more than one segment, but in this case you’ll just make one straight line. 12. Click the Create Profile Graph button. E10. Click the Interpolate Line button. Q46 USING ARCGIS 3D ANALYST
  • 54. The profile graph is created. You can see the graph on the layout of the map. 15. Click the Data View button to return to data view. You can edit the title, subtitle, and other properties of the graph; you can save, print, or export the graph; you can copy it to the clipboard; and you can show the graph on the layout. You can also simply close the graph. Y13. Right-click on the Profile Graph Title bar and click Show on Layout. Creating a line of sight on the terrain14. Close the profile graph window. Another way of understanding the terrain is to create a line of sight. Lines of sight show what parts of a surface are visible and what parts are hidden along a line from an R T observer point to a target point. 1. Click the Create Line of Sight button. 1QUICK-START TUTORIAL 47
  • 55. 2. Type “2” in the Observer offset text box. The line of sight is calculated. The green segments show areas that are visible from the observer point; the red segments are hidden from the observer. 2 The line of sight will be calculated to show what is visible from the perspective of an observer two meters tall, as the z units for this scene are meters.3. Click on the south slope of the higher land in the upper- right part of the TIN (the observer point), drag the line to the lower-right part, and release the mouse button (the target point). 4. Close the LineOfSight dialog box. 3 448 USING ARCGIS 3D ANALYST
  • 56. Lines of sight, like other graphic lines, can be copied 7. In ArcScene, click Edit and click Paste. from ArcMap to ArcScene. Now you will copy both the lines you’ve created into the scene.5. Click Edit and click Select All Elements. 7 The lines are pasted into the scene. 5 Both of the lines you created are selected.6. Click Edit and click Copy. 6QUICK-START TUTORIAL 49
  • 57. 8. In ArcScene, click the Save button. 89. In ArcMap, click File and click Exit. 910. Click No. Q50 USING ARCGIS 3D ANALYST
  • 58. Exercise 5: Working with animations in ArcSceneImagine that you wish to create an animated sequence 2. Navigate to the Exercise5 folder and double-click Finalshowing the flight of an object over a landscape. You’ve Animation_A.sxd.created a TIN and have draped images over it to show thearea. You also have some data pertaining to a strangephenomenon that has been occurring in the region. You areinterested in displaying all the data in a dynamic way,making an animation to tour points of interest, and showinghow you made the surface. You would also like to model 2the phenomenon by moving a layer in the scene.The tutorial data has already been assembled in the scenedocument named Animation.sxd. You will use ArcSceneanimation tools to effectively convey the points you want toshow. This scene contains geographic information and recordedData was supplied courtesy of MassGIS, Commonwealth of special effects that have been combined to make anMassachusetts Executive Office of Environmental Affairs. animation.In this exercise, you will play an existing animation in thescene document, Final Animation_A.sxd, and perform thetasks typically used to create the animation.Opening the Final Animation_A scene documentIn this section, you will play an animation that demonstratessome of the effects that you can create when you animatea scene.1. In ArcScene, click File and click Open. 1QUICK-START TUTORIAL 51
  • 59. Playing the scene’s animation This animation shows the flight of a hypothetical unidentified flying object (UFO) over the terrain.In order to view a scene’s animation, you need to turn onthe Animation toolbar. 3. Click the Play button.1. Click View, point to Toolbars, and click Animation. 3 The animation plays, illustrating some of the effects you can use in an animated scene. 1 The Animation toolbar appears. Now you’ll play the animation.2. Click the Open Animation Controls button. In the next section you will work through the steps used to make animations like this one. 252 USING ARCGIS 3D ANALYST
  • 60. Opening the Animation scene document The scene contains an ortho photo, a scanned topographic map, and other data you need to make your1. In ArcScene, click File and click Open. animation. 12. Navigate to the Exercise 5 folder and double-click Animation.sxd. 2QUICK-START TUTORIAL 53
  • 61. In this section, you’ll use the animation tools to capture For a camera keyframe, the object is the virtual camerakeyframes, import tracks, play back your animations, and through which you view the scene. Navigating the scenesave them to a scene document. changes camera properties that determine its position.There are three types of keyframes that you can use to ArcScene interpolates a camera path betweenbuild animations. The first is a camera keyframe. A camera keyframes, so you’ll need to capture more views tokeyframe is a snapshot of the view you see in a scene. The make a track that shows animation.second, a layer keyframe, is a snapshot of a layer’s 2. Right-click on UFO.lyr and click Zoom To The third type is a scene keyframe, which storesproperties of a scene. In this section, you will create asimple animation from a set of camera keyframes.Capturing Perspective views as keyframes to 2make an animationThe simplest way to make animations is by capturing views 3. Click the Capture View button to create a camerato be stored as keyframes. The captured views are keyframe showing the UFO layer.snapshots of camera perspectives in a scene at a particulartime. The most fundamental element of an animation is akeyframe. Keyframes are used as snapshots to interpolatebetween in a track. You’ll create a set of keyframes tomake a camera track that will show an animation between 3points of interest in your study area.1. Click the Capture View button to create a camera 4. Click the Full Extent button to view all the data. keyframe showing the full extent of the scene. 4 154 USING ARCGIS 3D ANALYST
  • 62. 5. Click Zoom In on the Navigation toolbar and zoom to 8. Zoom to Littleville Lake. Goss Heights, located near the center of your view. 8 5 9. Click the Capture View button to capture a view of6. Click the Capture View button to create a camera Littleville Lake. keyframe of Goss Heights. 9 6 10. Click the Full Extent button.7. Click the Full Extent button. Q 7QUICK-START TUTORIAL 55
  • 63. The captured views you just made are stored as a set of 3. Click the Play keyframes in a camera track. When the track isplayed, it shows a smooth animation between thekeyframes. Next, you’ll play your animation track.Playing back your animationYou will play back animations using simple tools thatresemble the controls of a video cassette recorder (VCR). 31. Click the Open Animation Controls button. An animation is played back by interpolating the camera position between the keyframes in the track. In this case, the animation shows a virtual tour through the views you captured. 12. Click the Animation toolbar and drag it to the lower-left corner of the scene so it won’t block your view of the tools or data. 256 USING ARCGIS 3D ANALYST
  • 64. Clearing an animation Recording navigationIf you want to start over, you can erase all the tracks you Another way to create a camera track for an animation iscreated. In this section, you’ll remove the tracks you just to record in real time while you navigate in a scene. In thiscreated so you can improve your animation. section, you will record your view of the scene while you1. Click Animation and click Clear Animation. navigate using the Fly tool. All animation tracks are removed from the scene. 1. Click the Fly tool on the navigation toolbar. The Fly tool allows you to fly through your scenes. 1 1 2. Click the Record button to start recording your navigation. 2 ArcScene begins recording as soon as you click the Record button. If you don’t navigate right away, your track will reflect this.QUICK-START TUTORIAL 57
  • 65. Exercise 6: ArcGlobe basics 2. In the table of contents, click the Type tab.Learning how to navigate in ArcGlobe helps you understandhow you can explore your data and teaches you how toaccomplish fundamental tasks that you will use as yourArcGlobe experience grows. 2In this exercise you’ll learn how to use the ArcGlobenavigation tools and how to set properties that enhance your ArcGlobe categorizes layers according to their type.viewing experience. This exercise assumes that you are Layers are classified as elevation, draped, or floating.using ESRI-supplied default layers. Elevation layers are raster sources with height information. They give the globe surface terrain. DrapedExamining the default layers in ArcGlobe layers are features or rasters that use the elevationFirst, you’ll open ArcGlobe and learn what kind of data is layers as a source of their base heights. These layersincluded with ArcGlobe by default. appear draped over the globe surface. Floating layers are features or rasters that float independently of the1. Click the Start menu, point to Programs, then ArcGIS, terrain surface. They appear offset from other layers, and click ArcGlobe. either draped on discrete surfaces or set to some constant elevation. Note the way the default layers are categorized. Notice the default layers listed in the Type page of the ArcGlobe TOC. Both layers are draped layers and, therefore, appear draped on the globe surface. 1 Adding more layers Default layers serve as a background to any data that you want to add to ArcGlobe. Next you’ll add some local data for the Las Vegas area. 1. Click the Add Data button. ArcGlobe opens and its default layers are loaded. Notice the layers that are loaded in the globe by looking at the list in the table of contents. 1 58 USING ARCGIS 3D ANALYST
  • 66. 2. Navigate to the location of the Exercise 6 tutorial data Changing a layer’s drawing priority in the table of folder. contents3. Click las_vegas_area.img, press Shift, and click Draped layers that have overlapping extents need to have a las_vegas_strip.img. drawing priority set so one layer gets drawn on top of the The layers are multiply selected. other. ArcGlobe makes some guesses to accomplish this, using criteria such as the cell size of a raster layer. Occasionally, you’ll need to override the ArcGlobe default 2 drawing priorities. One way to do this is to change the order of draped layers as they appear in the Type page of the table of contents. 1. Click the Countries layer and drag it so it is just above the World Image layer. A black line indicates where the layer will be placed. 4 1 34. Click Add. The image layers are added to ArcGlobe as draped layers. You’ll explore them later in the exercise. 2 2. Release the mouse pointer to drop the layer in its new position. The drawing priority is now set so las_vegas_area.img and las_vegas_strip.img get drawn on top of the Countries layer.QUICK-START TUTORIAL 59
  • 67. Navigating in Globe mode 1. Click the globe, slowly drag up and to the right, then release the mouse.ArcGlobe has two viewing modes: Globe mode and Surfacemode. Globe mode allows you to navigate your data in therealm of the whole globe and sets the camera target to thecenter of the globe. Surface mode lets you work with yourdata at a lower elevation, allows additional perspective 1viewing characteristics, and sets the camera target on thesurface of the globe. In this section, you’ll learn how tonavigate in Globe mode.The Navigate tool is active when you start ArcGlobe. Youcan see the names of other tools on the Tools toolbar byhovering the pointer over the tool. The globe rotates and the view angle lowers, so you gain a Zoom In/Out different vantage point. 2. Right-click and drag down. Navigate 2 The pointer changes to the Zoom In/Out pointer, and the view zooms in on the globe. To zoom out, right-click the globe and drag up.60 USING ARCGIS 3D ANALYST
  • 68. 3. Click Full Extent. Using the Spin tools 1. Click the Spin Clockwise button. 3 The globe displays at full extent. 1Turning on the Spin toolbar The globe continuously spins clockwise around the z-You can use the Spin toolbar to automatically spin the globe axis. You can change the speed at which it spins.clockwise or counterclockwise at any speed you wish. 2. Click the Up arrow on the Speed text box to increase the1. Right-click in the menu area and click Spin. rate at which the globe spins. 2 1 Continued clicks will incrementally increase the spin rate. You can also type in a value. Click the Down arrow The Spin toolbar appears as an undocked toolbar. to decrease the rate. 3 3. Click the Stop button to stop the globe from spinning. You can also press Esc to stop the globe from spinning.QUICK-START TUTORIAL 61
  • 69. Finding places on the globe 2 3 4If you have an Internet connection, you can find worldlocations by using the ArcWeb Place Finder in the Finddialog box.1. Click the Find button. 12. Click ArcWeb Place Finder.3. In the Find place text box, type “Las Vegas”.4. Click Find.5. Right-click on Las Vegas, Nevada, United States and click Zoom and create bookmark. The display zooms to Las Vegas, Nevada. 5 6. In the 3D Bookmark text box, type “Las Vegas Area”. 6 7 7. Click OK.62 USING ARCGIS 3D ANALYST
  • 70. 8. Click Cancel to close the Find dialog box. The display zooms to the Strip area of Las Vegas. 2. Click the Center on Target button. 8 2 3. Click the center of the Fountains of Bellagio.The Find tool is an easy way of locating almost any place inthe world. Use it to locate points of interest, then usebookmarks to save perspectives of these places. 3Now that you’re zoomed close to the globe surface, you’lllearn how to navigate in Surface mode.Navigating in Surface modeWhen you zoom in close to your data, you can switch toSurface mode to make your navigation apply more correctlyto your new environment. Switching to Surface modeplaces the camera target on the globe surface and givesyou a sense of gravity while you navigate your data.1. In the table of contents, right-click las_vegas_strip.img The point you clicked is moved to the center of the and click Zoom To Layer. display. Centering on a target sets a target on the globe surface and switches to Surface mode. 1QUICK-START TUTORIAL 63
  • 71. 4. Click Zoom to Target and click the central dome of the The globe rotates, and the viewing angle lowers. The Bellagio. horizon becomes visible with a light blue background, and you view the globe in a new perspective. 7. Click the Full Extent button to return the globe to its full extent position. 4 7 Setting some preferences You can modify the way ArcGlobe functions at both the globe level and the application level. First, you’ll explore A new target is centered and the display is zoomed to it. some application-level options.5. Click the Navigate button. 1. Click Tools and click Options. 56. Click the bottom of the display and slowly drag up. 6 1 The Options dialog box is where you set application-level preferences. The settings will be preserved in all instances of ArcGlobe.64 USING ARCGIS 3D ANALYST
  • 72. 2. Click General.3. Check Animate viewer when using tools and commands. 2 5 The display moves to the Las Vegas bookmark in a smooth, animated transition. Next, you’ll examine a document-level option. 3 4 This option will show smooth transitions from one view to the next when you use tools that change your perspective. This will be the standard behavior every time you open ArcGlobe until you turn off the option.4. Click OK.5. Click View, click Bookmarks, and click Las Vegas Area.QUICK-START TUTORIAL 65
  • 73. Setting a document-level option 21. Double-click Globe layers. 12. Click the Background tab.3. Click the Sky color dropdown arrow and click a color of the morning or evening sky. 366 USING ARCGIS 3D ANALYST
  • 74. Sky color is the color of the background when you zoom in close to your globe as defined by the lower limit of the transition zone.4. Click OK. 4 If you switch to Surface mode and lower the viewing angle, you’ll notice the background color changing to the color you indicated. Use different background colors to convey different moods.In this exercise you’ve learned how to differentiatebetween ArcGlobe layer types, navigate in Surface andGlobe modes, find places, and set some application andglobe properties. Now that you’ve learned somefundamentals, you can begin to explore other areas ofArcGlobe. In the next exercise, you’ll learn how to use dataas different layer categories.QUICK-START TUTORIAL 67
  • 75. Exercise 7: ArcGlobe layerclassification 2ArcGlobe classifies layers into three types to help youbetter manage them: elevation layers, draped layers, and 3. Right-click Globe layers, point to Add Data, and clickfloating layers. In this exercise, you’ll learn how to use the Add elevation data.classifications to help layers provide the right information toyour documents. This exercise assumes that you are usingESRI-supplied default layers.Adding elevation layers 3Elevation layers provide height information to the globesurface. You’ll use rasters with height source information toprovide topography to the globe surface, making it a globe Indicating that you want to add a specific type of dataterrain. adds layers into that category.1. Click the Start menu, point to Programs, then ArcGIS, 4. Navigate to the location of the Exercise7 folder. and click ArcGlobe. 5. Select sw_usa_grid. 4 1 5 6 ArcGlobe opens, and its default layers are loaded.2. In the TOC, click Type to show the page of the TOC 6. Click Add. that indicates layer classifications.68 USING ARCGIS 3D ANALYST
  • 76. The raster is added to the Elevation category and will be The layers are both selected. used as a source of elevation for the globe surface. 3. Click Add.Adding draped layers 4. Right-click angelus oaks.tif and click Zoom To Layer.Layers classified as draped are placed on the globe surfaceand use any elevation data present to show base heights.Next, you’ll add some images that will be draped on theglobe terrain you created.1. Right-click Globe layers, point to Add Data, and click Add draped data. 4 1 The display zooms to the extent of the layer. A few Layers you now choose to add will be draped on the moments will pass before the layer is shown at full globe terrain. resolution as the on-demand cache is built. Once the2. Click angelus oaks.tif, press Ctrl, and click cache is built, you’ll be able to revisit the area and socal_mmosaic.jpg. display the layer quickly. The Angelus Oaks imagery appears washed out due to the Countries layer being drawn with a higher drawing priority. Next, you’ll learn how to change a draped layer’s drawing priority. 2 3QUICK-START TUTORIAL 69
  • 77. Changing a layer’s drawing priority in the table of Setting a target to initiate Surface modecontents 1. Press Ctrl and click in the middle of the display.Draped layers that have overlapping extents need to have adrawing priority set so one layer gets drawn on top of theother. ArcGlobe makes some guesses to accomplish this,using criteria such as the cell size of a raster layer.Occasionally, you’ll need to override the ArcGlobe defaultdrawing priorities. One way to do this is to change the orderof draped layers as they appear in the Type page of thetable of contents. 11. Click the Countries layer and drag it so it is just above the World Image layer. A black line indicates where the layer will be placed.2. Release the mouse pointer to drop the layer in its new position. You’ve initiated Surface mode and set a target at the location on the globe surface where you clicked. 1 2 The drawing priority is now set so angelus oaks.tif and socal_mmosaic.sid get drawn on top of the Countries layer.70 USING ARCGIS 3D ANALYST
  • 78. 2. Click the bottom of the display and slowly drag up. Adding floating layers The globe terrain you created becomes discernible as Floating layers are layers that float independently of the you investigate the imagery you added. globe surface. Next, you’ll add a raster as a floating layer and set it to elevations not connected with the globe surface. 1. Click Globe layers, point to Add Data, and click Add 2 floating data. 1 2. Click o3_99x10k.3. Click the Full Extent button to return the display to the original view. 2 3 3 o3_99x10k is a raster showing average annual ozone concentration for 1999 in California. 3. Click Add. The layer is added to the Floating category.QUICK-START TUTORIAL 71
  • 79. Setting elevation properties of floating layers 21. Right-click o3_99x10k and click Properties. 3 4 1 3. In the Layer floats independent of the globe surface, draped on dropdown menu, click Elevation values provided by this layer .2. Click the Elevation tab. 4. In the Add a constant elevation offset in meters text box, type “5000”.72 USING ARCGIS 3D ANALYST
  • 80. 5. Click Symbology. Setting a vertical exaggeration factor for floating layers 5 1. Right-click o3_99x10k and click Zoom To Layer. 6 1 7 8 The layer is displayed in the view.6. In the Color Ramp dropdown menu, select the red to 2. Click the Navigation Mode button to change the mode to blue color ramp. Surface navigation.7. Check Invert. This inverts the color ramp so that high values will be 2 displayed as red, low values as blue.8. Click OK. You’ve set the raster to use its own values as a source of base heights, offset those heights 5,000 meters from the globe surface, and symbolized the concentration values with color. Next you’ll take a look at how this appears in the display and set a vertical exaggeration to accentuate the elevation.QUICK-START TUTORIAL 73
  • 81. 3. Click the bottom of the display and slowly drag the 6. In the Vertical Exaggeration Of floating layers dropdown cursor up. menu, select or type a value of “10”. 5 3 This will allow you to see the effect of changing the 6 vertical exaggeration.4. Double-click Globe layers. 45. Click the General tab. 7 The floating layer will be exaggerated by a factor of 10. 7. Click OK.74 USING ARCGIS 3D ANALYST
  • 82. Examine the floating layer you’ve created. You’ll see a 3D raster showing average ozone concentrations in California in 1999. The layer floats above the state of California and is a surface that is different from the terrain below.In this exercise, you learned how to differentiate layer typesin ArcGlobe, saw the effect they have on the globe, and setproperties to improve their display. Explore Exercise7.3ddglobe document in the Exercise7 folder to discoveradditional ways to enhance your globe documents. Thedocument contains layers saved with custom settings,bookmarks, globe lighting, and animation tracks.QUICK-START TUTORIAL 75
  • 83. Creating surface modelsIN THIS CHAPTER 3 3D Analyst lets you work with real or hypothetical surfaces with two types of surface models: rasters and TINs. You can use existing models, or you• Representing surfaces with can create your own from a variety of data sources. The two main methods rasters and TINs of creating surface models are by interpolation and triangulation. You can• Creating a raster from points choose from several interpolation methods, including Inverse Distance Weighted, Spline, Kriging, and Natural Neighbors interpolation. You can• Interpolator assumptions build triangulated surfaces by creating a TIN or by adding elements to an existing TIN. You can also convert between TIN and raster surface models.• Raster output controls• Creating a TIN from vector data• Modifying a TIN• Creating a TIN from a raster• Creating a raster from a TIN 77
  • 84. What are surfaces and surface models?A surface is a continuous field of values that may vary over an Raster surfacesinfinite number of points. For example, points in an area on theearth’s surface may vary in elevation, proximity to a feature, or Raster surfaces are usually stored in grid format. A grid consistsconcentration of a particular chemical. Any of these values may of a rectangular array of uniformly spaced cells with represented on the z-axis in a three-dimensional x,y,z The smaller the cells, the greater the locational precision of thecoordinate system, so they are often called z-values. grid.Because a surface contains an infinite number of points, it isimpossible to measure and record the z-value at every point.Surface models allow you to store surface information in a GIS.A surface model approximates a surface by taking a sample ofthe values at different points on the surface and then interpolatingthe values between these points. Higher precision grid Lower precision grid You cannot locate individual features—for example, the summit of a mountain—any more precisely than the size of the grid cells. Rasters are also used to store images and thematic grid data.Surface model of chemical concentration across an area withpoints showing where the concentration was sampled3D Analyst uses two types of surface models: rasters and TINs.Rasters represent a surface as a regular grid of locations withsampled or interpolated values. TINs represent a surface as a setof irregularly located points linked to form a network of triangleswith z-values stored at the nodes. Grid in perspective view 78 USING ARCGIS 3D ANALYST
  • 85. TIN surfaces The input features used to create a TIN remain in the same position as nodes or edges in the TIN. This allows a TIN toTINs consist of nodes that store z-values, connected by edges to preserve all of the precision of the input data whileform contiguous, nonoverlapping triangular facets. The edges in simultaneously modeling the values between known points. YouTINs can be used to capture the position of linear features that can include precisely located features on a surface—such asplay an important role in the surface, such as ridgelines or stream mountain peaks, roads, and streams—by using them as inputcourses. features to the TIN. TIN models are less widely available than raster surface models and tend to be more expensive to build and process. The cost of obtaining good source data can be high, and processing TINs tends to be less efficient than processing raster data because of their complex data structure. TINs are typically used for high precision modeling of smaller areas, such as in engineering applications, where they are useful because they allow calculations of planimetric area, surface area,Nodes and edges of a TIN Nodes, edges, and faces and volume.Because the nodes can be placed irregularly over the surface,TINs can have a higher resolution in areas where a surface ishighly variable or where more detail is desired and a lowerresolution in areas that are less variable or of less interest.TIN in perspective viewCREATING SURFACE MODELS 79
  • 86. Creating raster surfaces from pointsSurfaces of continuous data are usually generated from samples close together tend to have similar characteristics. For instance, iftaken at points across the area. For example, the irregularly it is snowing on one side of the street, you can predict with a highspaced weather stations in a region can be used to create raster level of confidence that it is also snowing on the other side of thesurfaces of temperature or air pressure. The resulting surface is a street. You would be less sure if it was snowing across town andregular grid of values. less confident still about the state of the weather in the next county.What is interpolation? Why interpolate?Interpolation predicts values for cells in a raster from a limitednumber of sample data points. It can be used to predict unknown Visiting every location in a study area to measure the height,values for any geographic point data: elevation, rainfall, chemical magnitude, or concentration of a phenomenon is usually difficultconcentrations, noise levels, and so on. or expensive. Instead, dispersed sample input point locations can be selected, and a predicted value can be assigned to all other locations. Input points can be either randomly, strategically, or regularly spaced points containing height, concentration, or magnitude measurements. A typical use for point interpolation is to create an elevation surface from a set of sample measurements. Each point represents a location where the elevation has been measured. The values between these input points are predicted by interpolation. LowOn the left is a point dataset of known values. On the right is a rasterinterpolated from these points. Unknown values are predicted with amathematical formula that uses the values of nearby known points.In this example the input points happen to fall on cell centers—this is unlikely in practice. One problem with creating rasters byinterpolation is that the original information is degraded to someextent—even when a data point falls within a cell, it is not Highguaranteed that the cell will have exactly the same value.Interpolation is based on the assumption that spatially distributedobjects are spatially correlated; in other words, things that are The resulting grid is a prediction of what the elevation is at any location on the actual surface. 80 USING ARCGIS 3D ANALYST
  • 87. Interpolation methods have to specify parameters, such as radius, number of neighbors, or weights.There are several ways to create raster surfaces from point data.You can use the IDW, Natural Neighbors, Spline, and Kriging Spline: This general-purpose interpolation method fits amethods to create surfaces through the user interface of minimum-curvature surface through the input points.3D Analyst. Trend surface interpolation is available through Conceptually, this is like bending a sheet of rubber to passcustomization. through the points while minimizing the total curvature of the surface. It fits a mathematical function—a minimum curvature,Each interpolation method makes assumptions about how to two-dimensional, thin-plate spline—to a specified number of thedetermine the estimated values. Depending on the phenomenon nearest input points while passing through all input points. Thisyou are modeling and the distribution of sample points, different method is best for gradually varying surfaces such as elevations,interpolators produce better models of the actual surface. water-table depths, or pollution concentrations. It is notRegardless of the interpolator, the more input points and the more appropriate when there are large changes within a shorteven their distribution, the more reliable the results. horizontal distance because it can overshoot estimated values.Inverse Distance Weighted: This interpolation method assumes Kriging: This interpolation method assumes that the distance orthat each sample point has a local influence that diminishes with direction between sample points reflects a spatial correlation thatdistance. It weights the points closer to the processing cell more can be used to explain variation in the surface. Kriging fits aheavily than those farther away. Either a specified number of mathematical function to a specified number of points, or allpoints or all of the points within a given radius can be used to points within a specified radius, to determine the output value fordetermine the value of each output cell. This method is each location. Kriging is a multistep process; it includesappropriate when the variable being mapped decreases in exploratory statistical analysis of the data, variogram modeling,influence with distance from the sampled location. For example, creating the surface, and, optionally, exploring a variance surface.when interpolating a surface of consumer purchasing power for a This function is most appropriate when you know there is aretail site analysis, the purchasing power of a more distant spatially correlated distance or directional bias in the data. It islocation will have less influence because people are more likely often used in soil science and shop closer to home. Trend: This interpolation method fits a mathematical function—aNatural Neighbors: Like IDW, this interpolation method is a polynomial of specified order—to all input points. This methodweighted-average interpolation method. However, instead of uses a least-squares regression fit, which results in a surface thatfinding an interpolated point’s value using all of the input points minimizes the variance of the surface in relation to the inputweighted by their distance, Natural Neighbors interpolation values. The surface is constructed so that for every input point,creates a Delauney Triangulation of the input points and selects the total of the differences between the actual values and thethe closest nodes that form a convex hull around the interpolation estimated values (the variance) will be the smallest possible. Thepoint, then weights their values by proportionate area. This resulting surface rarely goes through the input points. The Trendmethod is most appropriate where sample data points are method is available through customization but not through the 3Ddistributed with uneven density. It is a good general-purpose Analyst user interface.interpolation technique and has the advantage that you do notCREATING SURFACE MODELS 81
  • 88. Details on the interpolation methods Radius Type: VariableOf the available interpolation methods, IDW, Spline, and Kriging, With a variable radius, the number of points used in calculatingeach has some parameters that influence how the interpolation is the value of the interpolated point, or count, is specified. Thisdone. The Natural Neighbors method only requires that you makes the radius vary for each interpolated point, depending onspecify the output cell size. how far it has to search around each interpolated point to reach the specified number of input points. The variable radiusInverse Distance Weighted approach may produce better surfaces when the density of input points varies significantly from one area to another. If you knowIDW estimates grid cell values by averaging the values of sample you have areas with sparsely distributed input points, you candata points in the vicinity of each cell. The closer a point is to the specify a maximum distance to limit the potential radius of thecenter of the cell being estimated, the more influence, or weight, circle. In this case, if the number of points is not reached beforeit has in the averaging process. There are several parameters you the maximum distance of the radius is reached, fewer points willcan set to control the IDW interpolation. These are the Power, the be used in the calculation of the interpolated point.Radius Type, and Barriers. Barrier: A line or polygon dataset can be used as a break thatPower: With IDW you can control the significance of known limits the search for input sample points. A line can represent apoints on the interpolated values based on their distance from the cliff, ridge, or some other interruption in a landscape. Only thoseoutput point. By defining a high power, more emphasis is placed input sample points on the same side of the barrier as the currenton the nearest points, and the resulting surface will have more processing cell will be considered. A choice of No Barriers willdetail (be less smooth). Specifying a lower power will give more use all points within the identified radius.influence to the points that are further away, resulting in asmoother surface. A power of 2 is most commonly used and is the Splinedefault. Spline estimates values using a mathematical function thatThe characteristics of the interpolated surface can also be minimizes overall surface curvature, resulting in a smooth surfacecontrolled by limiting the number of input points used for that passes exactly through the input points.calculating each interpolated point: There are two Spline methods: Regularized and Tension. TheyRadius Type: Fixed are described below, as well as the meaning of the weightWith a fixed radius, the distance of the radius is constant, and for parameter, which changes depending on the Spline method. Botheach interpolated point, all of the points within the circle will be methods share a number of points parameter.used. By specifying a minimum count, you can ensure that if in a Number of points: For both methods, this parameter defines thecertain area the number of points is less than the count specified, number of points used in the calculation of each interpolatedthe radius of the circle will be increased until the count is met. point. The more input points you specify, the more each cell is influenced by distant points, and the smoother the surface. 82 USING ARCGIS 3D ANALYST
  • 89. Regularized spline Kriging is similar to IDW in that it weights the surroundingThe Regularized method creates a smooth, gradually changing measured values to derive a prediction for an unmeasuredsurface with values that may lie outside the sample data range. location. The general formula for both interpolators is formed as a weighted sum of the data:Weight: Defines the weight of the third derivatives of thesurface in the curvature minimization expression. The higher the Nweight, the smoother the surface. Z (s 0 ) = ∑ λi Z (si ) ˆ i =1The values entered for this parameter must be equal to or greaterthan zero. The typical values that may be used are 0, .001, .01,.1, and .5. whereTension spline Z(si) is the measured value at the ith location;The Tension method tunes the stiffness of the surface according λι is an unknown weight for the measured value at the ithto the character of the modeled phenomenon. It creates a less location;smooth surface with values more closely constrained by thesample data range. s0 is the prediction location;Weight: Defines the weight of tension. The higher the weight, N is the number of measured values.the coarser the surface. In IDW, the weight, λι, depends solely on the distance to theThe values entered have to be equal to or greater than zero. The prediction location. However, in Kriging, the weights are basedtypical values are 0, 1, 5, and 10. not only on the distance between the measured points and the prediction location but also on the overall spatial arrangementKriging among the measured points. To use the spatial arrangement in the weights, the spatial autocorrelation must be quantified. Thus, inIDW and Spline (discussed earlier) are referred to as Ordinary Kriging, the weight, λι, depends on a fitted model to thedeterministic interpolation methods because they are directly measured points, the distance to the prediction location, and thebased on the surrounding measured values or on specified spatial relationships among the measured values around themathematical formulas that determine the smoothness of the prediction location.resulting surface. A second family of interpolation methods To make a prediction with Kriging, two tasks are necessary: (1) toconsists of geostatistical methods (such as kriging), which are uncover the dependency rules and (2) to make the predictions. Tobased on statistical models that include autocorrelation (the realize these two tasks, Kriging goes through a two-step process:statistical relationship among the measured points). Because of (1) the creation of variograms and covariance functions tothis, not only do these techniques have the capability of estimate the statistical dependence—called spatialproducing a prediction surface, but they can also provide some autocorrelation—values, which depends on your model ofmeasure of the certainty or accuracy of the predictions. autocorrelation—fitting a model—and (2) actually predicting theCREATING SURFACE MODELS 83
  • 90. unknown values—making a prediction. It is because of these two Often each pair of locations has a unique distance, and there aredistinct tasks that it has been said that Kriging uses the data often many pairs of points. To plot all pairs quickly becomestwice: the first time to estimate the spatial autocorrelation of the unmanageable. Instead of plotting each pair, the pairs aredata and the second time to make the predictions. grouped into lag bins. For example, compute the average semivariance for all pairs of points that are greater than 40 metersVariography apart but less than 50 meters. The empirical semivariogram is a graph of the averaged semivariogram values on the y-axis and theFitting a model or spatial modeling is also known as structural distance, or lag, on the x-axis (see diagram below).analysis or variography. In spatial modeling of the structure ofthe measured points, you will begin with a graph of the empiricalsemivariogram, computed as: SemivarianceSemivariogram(distance h) = 0.5 * average[ (value at location i –value at location j)2]for all pairs of locations separated by distance h. The formulainvolves calculating the difference squared between the values ofthe paired locations. The image below shows the pairing of onepoint (the red point) with all other measured locations. Thisprocess continues for each measured point. Distance Spatial autocorrelation quantifies a basic principle of geography; things that are closer are more alike than things farther apart. Thus, pairs of locations that are closer—far left on the x-axis of the semivariogram cloud—should have more similar values—low on the y-axis of the semivariogram cloud. As pairs of locations become farther apart—moving to the right on the x-axis of the semivariogram cloud—they should become more dissimilar and have a higher squared difference—move up on the y-axis of the semivariogram cloud. 84 USING ARCGIS 3D ANALYST
  • 91. Fitting a model to the empirical semivariogram The diagrams below show two common models and identify how the functions differ:The next step is to fit a model to the points forming the empiricalsemivariogram. Semivariogram modeling is a key step between • The Spherical Modelspatial description and spatial prediction. The main application ofKriging is the prediction of attribute values at unsampled Semivariancelocations. You have seen how the empirical semivariogramprovides information on the spatial autocorrelation of datasets.However, it does not provide information for all possibledirections and distances. For this reason, and to ensure thatKriging predictions have positive Kriging variances, it isnecessary to fit a model (i.e., a continuous function or curve) tothe empirical semivariogram. Abstractly, this is similar toregression analysis, where a continuous line or curve is fitted.Select some function that serves as your model, for example, a Distancespherical type that rises at first and then levels off for largerdistances beyond a certain range (see previous image). There are This model shows a progressive decrease of spatialdeviations of the points on the empirical semivariogram from the autocorrelation—equivalently, an increase of semivariance—untilmodel; some points are above the model curve, and some points some distance, beyond which autocorrelation is zero. Theare below. But if you add the distance each point is above the line spherical model is one of the most commonly used models.and add the distance each point is below the line, the two values • The Exponential Modelshould be similar. There are a lot of different semivariogrammodels to choose from. SemivarianceDifferent types of semivariogram models3D Analyst provides the following functions to choose from tomodel the empirical semivariogram: Circular, Spherical,Exponential, Gaussian, and Linear. The selected model influencesthe prediction of the unknown values, particularly when the shapeof the curve near the origin differs significantly. The steeper thecurve is near the origin, the more influence the closest neighborswill have on the prediction. As a result, the output surface will beless smooth. Each model is designed to fit different types of Distancephenomenon more accurately.CREATING SURFACE MODELS 85
  • 92. This model is applied when spatial autocorrelation decreases Sample locations separated by distances closer than the range areexponentially with increasing distance. Here the autocorrelation spatially autocorrelated, whereas locations farther apart than thedisappears completely only at an infinite distance. The range are not.exponential model is also a commonly used model. The value at which the semivariogram model attains the range—The choice of which model to use in 3D Analyst is based on the the value on the y-axis—is called the sill. The partial sill is the sillspatial autocorrelation of the data and on prior knowledge of the minus the nugget (see the following section).phenomenon. The nuggetUnderstanding a semivariogram—the range, sill, and Theoretically, at zero separation distance (i.e., lag = 0), thenugget semivariogram value is zero. However, at an infinitely small separation distance, the semivariogram often exhibits a nuggetAs previously discussed, the semivariogram depicts the spatial effect, which is some value greater than zero. If the semivariogramautocorrelation of the measured sample points. Because of a model intercepts the y-axis at 2, then the nugget is 2.basic principle of geography—things that are closer are morealike—measured points that are close will generally have a smaller The nugget effect can be attributed to measurement errors ordifference squared than those farther apart. Once each pair of spatial sources of variation at distances smaller than the samplinglocations is plotted—after being binned—a model is fit through interval, or both. Measurement error occurs because of the errorthem. There are certain characteristics that are commonly used to inherent in measuring devices. Natural phenomena can varydescribe these models. spatially over a range of scales (i.e., micro or macro scales). Variation at micro scales smaller than the sampling distances willThe range and sill appear as part of the nugget effect. Before collecting data, it isWhen you look at the model of a semivariogram, you will notice important to gain some understanding of the scales of spatialthat at a certain distance the model levels out. The distance where variation that you are interested in.the model first flattens out is known as the range. Making a prediction γ(si,sj) The first task of uncovering the dependence (autocorrelation) in your data has been accomplished. You have also finished with the first use of the data, where the spatial information in the data—to compute distances—is used to model the spatial autocorrelation. Partial Sill Once you have the spatial autocorrelation, you proceed with Sill prediction using the fitted model; thereafter, the empirical semivariogram is set aside. Range Nugget 0 Distance 86 USING ARCGIS 3D ANALYST
  • 93. For the second task, you use the data again to make predictions. Using the configuration of the valid points within the specifiedLike IDW interpolation, Kriging forms weights from surrounding neighborhood around the prediction location in conjunction withmeasured values to predict at unmeasured locations. As with the model fit to the semivariogram, the weights for the measuredIDW interpolation, the measured values closest to the locations can be determined. From the weights and the values, aunmeasured locations have the most influence. However, the prediction can be made for the unknown value at the predictionKriging weights for the surrounding measured points are more location.sophisticated than those of IDW. IDW uses a simple algorithm 3D Analyst has two neighborhood types, fixed and variable.based on distance, but kriging weights come from asemivariogram that was developed by looking at the spatial Fixed search radiusnature of the data. To create a continuous surface or map of the A fixed search radius requires a distance and a minimum numberphenomenon, predictions are made for each location (cell of points. The distance dictates the radius of the circle of thecenters) in the study area based on the semivariogram and the neighborhood (in map units). The distance of the radius isspatial arrangement of measured values that are nearby. constant, so for each interpolated cell, the radius of the circle used to find input points is the same. The minimum number ofSearch radius points indicates the minimum number of measured points to useYou can assume that as the locations get farther from the within the neighborhood. All the measured points that fall withinprediction location, the measured values will have less spatial the radius will be used in the calculation of each interpolated cell.autocorrelation with the unknown value for the location you are When there are fewer measured points in the neighborhood thanpredicting. Thus, you can eliminate those farther locations with the specified minimum, the search radius will increase until it canlittle influence. Not only is there less relationship with farther encompass the minimum number of points. The specified fixedlocations, but it is also possible that the farther locations may search radius will be used for each interpolated cell (cell center)have a negative influence if they are located in an area much in the study area, thus if your measured points are not spread outdifferent than the prediction location. Another reason to use equally, which they rarely are, there likely will be a differentsearch neighborhoods is for computational speed. The smaller the number of measured points used in the different neighborhoodssearch neighborhood, the faster the predictions can be made. As a for the various predictions.result, it is common practice to limit the number of points that are Variable search radiusused when making a prediction by specifying a search With a variable search radius, the number of points used inneighborhood. The specified shape of the neighborhood restricts calculating the value of the interpolated cell is specified, whichhow far and where to look for the measured values to be used in makes the radius distance vary for each interpolated cell,the prediction. Other neighborhood parameters restrict the depending on how far it has to search around each interpolatedlocations that will be used within that shape so, for example, you cell to reach the specified number of input points. Thus, somecan define the maximum and minimum number of measured neighborhoods can be small and others can be large depending onpoints to use within the neighborhood. the density of the measured points near the interpolated cell. You can also specify a maximum distance—in map units—that theCREATING SURFACE MODELS 87
  • 94. search radius cannot exceed. If the radius for a particularneighborhood reaches the maximum radius before obtaining thespecified number of points, the prediction for that location willbe performed on the number of measured points within themaximum radius.Kriging methods3D Analyst provides two kriging methods: Ordinary andUniversal Kriging.Ordinary KrigingOrdinary Kriging is the most general and widely used of thekriging methods. It assumes the constant mean is unknown. Thisis a reasonable assumption unless there is some scientific reasonto reject this assumption.Universal KrigingUniversal Kriging assumes that there is an overriding trend in thedata (i.e., a prevailing wind) and it can be modeled by adeterministic function, a polynomial. This polynomial issubtracted from the original measured points, and theautocorrelation is modeled from the random errors. Once themodel is fit to the random errors, before making a prediction, thepolynomial is added back to the predictions to give youmeaningful results. Universal Kriging should only be used whenyou know there is a trend in your data and you can give ascientific justification to describe it. 88 USING ARCGIS 3D ANALYST
  • 95. Interpolating a Interpolating using Inverse Distanceraster surface Weighted with a variable 1You can create a new raster search radiussurface from input point data 1. Click 3D Analyst, point tousing four different interpolation Interpolate to Raster, andmethods. Each method has click Inverse Distanceparameters that you can modify create a raster that suits yourneeds. 2. Click the dropdown arrow and choose the input point data 2 source.Tip 3. Click the field that containsWhat is the power? the attribute data that youThe power is the exponent of thedistance used in IDW interpola- want to interpolate. 3tion. Higher numbers result in alower influence of distant points on 4. Type the power. 4each processing cell. Lower 5. Click the dropdown arrow and click Variable. 5numbers result in more smoothingof the surface. Reasonable power 6. Type the number of points tovalues range between 0.5 and 3. use as input from within the 6 maximum distance. 7Tip 7. Type the maximum distanceWhat is a variable radius? to search for points to use in 8A variable radius interpolation the interpolation. 9uses the closest n points that itfinds within the maximum distance 8. Optionally, check the box and select or navigate to a feature Qof the output cell as input. Incontrast, a fixed radius uses all of class to use as barriers tothe points within the specified interpolation.distance. 9. Type a cell size for the output raster. WTip 10. Optionally, type a name forWhat are barriers? the Output raster. If you doA feature class of linear features, not, the raster will besuch as faults or cliffs, can be used limit the search for input points 11. Click OK.for the interpolation of each outputcell.CREATING SURFACE MODELS 89
  • 96. Tip Interpolating usingWhat is the Minimum Inverse DistanceCount? Weighted with a fixed 1A fixed radius interpolation uses search radiusall of the points within thespecified distance. If no points are 1. Click 3D Analyst, point tofound within the search radius, the Interpolate to Raster, andsearch radius will increase for the click Inverse Distancecell until the specified minimum Weighted.number of points is found. 2. Click the dropdown arrow and choose the input point data 2 source. 3. Click the dropdown arrow and choose the field that contains the attribute data that you want to interpolate. 3 4. Type the power. 4 5. Click the dropdown arrow and 5 click Fixed. 6. Type the distance within 6 which to search for input points. 7 7. Type the minimum number of points that must be included 8 in the interpolation for a cell. 9 8. Optionally, check the box and select or navigate to a feature Q class to use as barriers to interpolation. 9. Type a cell size for the output raster. W 10. Optionally, type a name for the Output raster. If you do not, the raster will be temporary. 11. Click OK. 90 USING ARCGIS 3D ANALYST
  • 97. Tip Interpolating using aWhat is a Tension spline? Tension splineA spline interpolation is a method 1. Click 3D Analyst, point toof fitting a surface to a set ofpoints. Think of the surface as a Interpolate to Raster, and 1 click Spline.thin plate of slightly elasticmaterial deformed to fit the points. 2. Click the dropdown arrow andIn a Tension spline, you can choose the input point datacontrol the elasticity of the surface. source. 3. Click the dropdown arrow andTip choose the field that contains the attribute data that youWhat is the weight value? want to interpolate. 2The weight value in a Tensionspline adjusts the elasticity of the 4. Click the dropdown arrow and 3surface. A weight of 0 results in abasic thin-plate spline interpola- click Tension. 4tion. Larger values increase the 5. Type a weight. 5elasticity of the surface. Typicalweight values are 0, 1, 5, and 10. 6. Type the minimum number of 6 points that must be included in the interpolation for a cell. 7Tip 7. Type a cell size for the output 8 raster.What is the number ofpoints? 8. Optionally, type a name forThe number of points controls the the Output raster. If you doaverage number of points to be not, the raster will be 9contained in each region used in temporary.computing the surface. The regions 9. Click OK.are rectangles of equal size, andthe number of regions is deter-mined by dividing the total numberof input points by the number ofpoints. When the data is notuniformly distributed, the actualnumber of points in a region maybe different from the number ofpoints. If the number of points in aregion is less than eight, the regionis expanded until it contains eightpoints.CREATING SURFACE MODELS 91
  • 98. Tip Interpolating using aWhat is a Regularized Regularized splinespline? 1. Click 3D Analyst, point toA Regularized spline lets youcontrol the smoothness of the Interpolate to Raster, and 1surface. Regularized splines are click Spline.useful if you will need to calculate 2. Click the dropdown arrow andthe second derivative of the choose the input point datainterpolated surface. source. 3. Click the dropdown arrow andTip choose the field that containsWhat is the weight? the attribute data that youThe weight value in a Regularized want to interpolate. 2spline adjusts the smoothness ofthe surface. The weight specifies 4. Click the dropdown arrow and click Regularized. 3the weight (tau) attached to thethird derivative term, used in 5. Type a weight. 4minimizing the curvature of the 6. Type the minimum number of 5surface. Larger values result insmoother surfaces and smooth points that must be included 6 in the interpolation for a cell.first-derivative (slope) surfaces.Values between 0 and 0.5 are 7 7. Type a cell size for the outputsuitable. raster. 8 8. Optionally, type a name forTip the Output raster. If you doWhat is the number ofpoints? not, the raster will be temporary. 9The number of points controls theaverage number of points con- 9. Click OK.tained in each region used incomputing the surface. The regionsare rectangles of equal size; thenumber of regions is determined bydividing the total number of inputpoints by the number of points.When the data is not uniformlydistributed, the actual number ofpoints in a region may be differentfrom the number of points. If thenumber of points in a region is lessthan eight, the region is expandeduntil it contains eight points. 92 USING ARCGIS 3D ANALYST
  • 99. Kriging Creating a surface using Kriging interpolation withinterpolation a variable radiusThere are two kriging methods:Ordinary and Universal. 1. Click the 3D Analyst dropdown arrow, point to 1Ordinary Kriging is the most Interpolate to Raster, andgeneral and widely used of the click Kriging.kriging methods and is the 2. Click the dropdown arrow anddefault. It assumes the constant click the Input points dataset.mean is unknown. Universal 3. Click the Z value fieldKriging should only be usedwhen you know there is a trend dropdown arrow and click the field you wish to use. 2in your data and you can give ascientific justification to describe 4. Click the Kriging method you wish to using a variable search radius, 5. Click the Semivariogram model dropdown arrow and 3you can specify the number of click the model you wish to 4points to use in calculating thevalue of the interpolated cell. use. 5This makes the search radius 6. Click the Search radius typevariable for each interpolated dropdown arrow and click 6cell, depending on how far it has stretch to reach the specifiednumber of input points. 7. Optionally, change the default Number of points. 7 8. Optionally, specify a Maxi- 8Specifying a maximum distancelimits the potential size of the mum distance. 9radius of the circle. If the number 9. Optionally, change the defaultof points is not reached before Output cell size. Wthe maximum distance of theradius is reached, fewer points 10. Optionally, check the Create Prediction of standard errorwill be used in the calculation of check box.the interpolated cell. u 11. Specify a name for the Q E outputs or leave the default to create a temporary dataset in your working directory. 12. Click OK.CREATING SURFACE MODELS 93
  • 100. With a Fixed radius, the radius of Creating a surface usingthe circle used to find input Kriging interpolation withpoints is the same for each a fixed radiusinterpolated cell. The defaultradius is five times the cell size 1. Click the 3D Analystof the output grid. By specifying dropdown arrow, point to 1a minimum number of points, Interpolate to Raster, andyou can ensure that within the click Kriging.fixed radius, at least a minimum 2. Click the dropdown arrow andnumber of input points will be click the Input points dataset.used in the calculation of eachinterpolated cell. 3. Click the Z value field dropdown arrow and click the 2 field you wish to use.Tip 4. Click the Kriging method youDeciding on the radius or wish to use.the number of pointsUse the measure tool on the Tools 5. Click the Semivariogram 3toolbar to measure distance model dropdown arrow and click the model you wish to 4between points to get an idea of use. 5the radius and number of points touse. 6. Click the Search radius type dropdown arrow and click 6 Fixed.Tip 7. Optionally, change the default 7Changing the lag size,major range, partial sill, Distance for the search radius setting. 8and nuggetClick Advanced Parameters on the 8. Optionally, change the 9 Minimum number of points.Kriging dialog box to modify theseparameters. 9. Optionally, change the default W Output cell size. 10. Optionally, check the Create Prediction of standard error check box. Q E 11. Specify a name for the outputs or leave the default to create a temporary dataset in your working directory. 12. Click OK. 94 USING ARCGIS 3D ANALYST
  • 101. Tip Interpolating usingWhat is a Natural Natural NeighborsNeighbors interpolation? 1. Click 3D Analyst, point toA Natural Neighbors interpolation Interpolate to Raster, andcombines some TIN functionality click Natural Neighbors.with the raster interpolationprocess. The raster surface is 2. Click the dropdown arrow and 1interpolated using the input data choose the Input points datapoints that are natural neighbors source.of the cell. 3. Click the dropdown arrow andThe interpolation method first click the height source.creates a Delauney Triangulationof the input points (part of the TIN 4. Type a cell size for the outputcreation process); the points are raster.nodes in a triangulation that 5. Type a name for the Output 2follows the rule that a circle raster. 3around each triangle can containno other nodes. This means that, 6. Click OK. 4collectively, the triangles are 5constrained to be as close toequilateral triangles as possible.For each data point, the naturalneighbors are the minimumnumber of nodes in the triangula- 6tion that connect to form a convexhull around the point.The weight of each neighbor pointis determined through the use of aThiessen/Voroni technique thatevaluates its area of influence.CREATING SURFACE MODELS 95
  • 102. 1. Click 3D Analyst and clickSaving all rasters a specified 2. Click the General tab.location 3. Type the name of the new working directory.You can specify a folder where3D Analyst will save output Alternatively, you can browsetemporary rasters. Temporary to your new working directory. 1rasters are automatically deleted 4. Click OK.when you exit the applicationwhere they were created, unlessyou save a layer file, scene, ormap document that refers to the 2raster.There are two ways to specifywhere your analysis resultsshould go. The first way is to 3specify a location on disk foryour results using the AnalysisOptions dialog box before youperform any analysis. This wayall your analysis results will go tothis directory. The second way isto specify a location on disk eachtime you perform analysis in eachof the function dialog boxes.This is useful if you want to sortyour analysis results intodifferent folders. 4By default, temporary rasters aresaved to your system’s temporarydirectory, usually C:temp. 96 USING ARCGIS 3D ANALYST
  • 103. 1. Click 3D Analyst and clickSetting an Options.analysis mask 2. Click the General tab.An analysis mask is a raster that 3. Browse to the raster that willallows an analysis operation to be the analysis performed only on certain 4. Click OK.cells of interest in another raster.It contains selected cells that are 1of interest for future processingand other cells that are to be 2masked out. The masked-outcells should have a value ofnodata.Setting an analysis mask meansthat processing will only occur 3on selected cells and that allother cells will be assignedvalues of NoData.Setting an analysis mask is a two-step process:1. The analysis mask must first be created using the Reclassify dialog box. See the section on reclassifying rasters for more information about creating an 4 analysis mask.2. The analysis mask must then be specified in the General tab of the Analysis Options dialog box in order for it to be used in all subsequent analysis.Analysis masks will work on theoutput of the surface analysistools in 3D Analyst.CREATING SURFACE MODELS 97
  • 104. 1. Click 3D Analyst and clickSetting the Options.coordinate 2. Click the General tab.system for your 3. Click the Analysis Coordinate System option you wish toanalysis results use to save your analysis results into either the coordi-Rasters with different coordinatesystems can be projected on the nate system of the input 1fly into a single data frame with a raster or the coordinategiven coordinate system for system of the data frame.display and analysis in ArcMap. 4. Click OK.When you have rasters in more 2than one coordinate system inyour scene or map, you need tospecify the coordinate system forthe output of the analysis tools. 3 4 98 USING ARCGIS 3D ANALYST
  • 105. Setting the output Specifying an extent for analysis resultsextent 1. Click 3D Analyst and clickThe extent of a layer is the x,y Options.coordinates for the bottom-left 2. Click the Extent tab.and the top-right corners. 3. Click the Analysis extentYou can control how the output dropdown arrow and choose 1raster extent is determined for the an option to specify theInterpolation and Analysis tools. extent for all subsequentBy default, the output extent isthe same as the input dataset’s analysis results. 2extent. 4. Click OK.You may only wish to performanalysis on the area visible in themap (‘Same As Display’), or you 3may wish to make the extent thesame as another layer in the tableof contents (‘Same As Layer’).Alternatively, you can specify acustom extent (‘As SpecifiedBelow’).TipSetting the Snap extentSetting the Snap extent to aspecific grid will snap all layers tothe cell registration of the specified 4grid. All layers will share thelower left corner and cell size ofthe specified grid. Use this toresample layers to the sameregistration and cell size in orderto perform analysis.CREATING SURFACE MODELS 99
  • 106. Setting the output Setting the cell sizecell size 1. Click 3D Analyst and click Options.You can control the default size 2. Click the Cell Size tab.of the cells in your output rasters.By default, the output cell size is 3. Click the dropdown arrow andthe same as the input datasets cell choose the method ofsize. You can change the output determining the cell size. 1cell size to be the cell size of a 4. Optionally, type the number ofdataset in the current scene or map units to define the cellmap or a cell size that you define. size. 2Exercise caution when specifying 5. Optionally, type the number ofa cell size finer than the input rows and the number ofgrids. No new data is created; columns to define a cell size.cells are interpolated usingnearest-neighbor resampling. The 6. Click OK. 3result is as precise as the coarsest 4input. 5TipOverriding the default cellsizeEven if you’ve set a particular cellsize on the Options dialog box, youcan override the cell size for aparticular analysis tool by settingthe cell size on the tool. 6100 USING ARCGIS 3D ANALYST
  • 107. Creating TIN surfaces from vector dataTINs are usually created from a combination of vector data TINs allow you to model heterogeneous surfaces efficiently bysources. You can use point, line, and polygon features as input including more mass points in areas where the surface is highlydata for a TIN. Some of these input features should have variable and fewer in places where the surface is less variable.z-values, though not all of the features need z-values. The input Breaklines are lines with or without height measurements. Theyfeatures to a TIN may also contain integer attribute values that become sequences of one or more triangle edges.are preserved in the resulting TIN features. These may be used toindicate the relative accuracy of different input data or to identifyfeatures, such as roads or lakes.Building a TINYou can create a TIN all at once from one or more kinds of inputdata, you can create it in stages, or you can add data to refine anexisting TIN. TINs are made from mass points, breaklines, andpolygons. Mass points are point height measurements; theybecome nodes in the network. Mass points are the primary inputinto a TIN; they determine the overall shape of the surface. Breaklines Breaklines typically represent either natural features, such as ridgelines or streams, or built features, such as roadways. There are two kinds of breaklines: hard and soft. Hard breaklines represent a discontinuity in the slope of the surface. Streams and road cuts could be included in a TIN as hard breaklines. Hard breaklines capture abrupt changes in a surface and improve the display and analysis of TINs. Soft breaklines let you add edges to a TIN to capture linear features that do not alter the local slope of a surface. Study areaMass points, categorized by height attributeCREATING SURFACE MODELS 101
  • 108. boundaries could be included in a TIN as soft breaklines to Replace polygons set the boundary and all interior heights to thecapture their position, without affecting the shape of the surface. same value. A replace polygon could be used to model a lake orPolygons represent surface features with area—such as lakes—or an area on a slope excavated to a level surface.boundaries—also called hulls—of separately interpolated areas. Fill polygons assign an integer attribute value to all triangles that fall within the fill polygon. The surface height is unaffected, and no clipping or erasing takes place.Clip polygon The graphic on the left shows a TIN created from mass points; the graphic on the right shows a TIN of the same area created from mass points andHulls could define the shores of individual islands in an breaklines.archipelago, or the boundary of a study area. Polygon features are integrated into the triangulation as closedThere are four polygon surface feature types: clip polygons, erase sequences of three or more triangle edges.polygons, replace polygons, and fill polygons. Including breaklines and polygons in a TIN gives you moreClip polygons define a boundary for interpolation. Input data that control over the shape of the TIN surface.falls outside of the clip polygon is excluded from theinterpolation and analysis operations—for example, contouring To get a sense of the difference that breaklines can make in aor volume calculations. TIN, compare the surface created from mass points alone to the surface created from mass points and breaklines.Erase polygons define a boundary for interpolation. Input datathat falls within the erase polygon is excluded from theinterpolation and analysis operations—for example, contouringor volume calculations.102 USING ARCGIS 3D ANALYST
  • 109. Building a TIN Creating a TINTINs are often created from a 1. Click 3D Analyst, point to 1 Create/Modify TIN, and clickgroup of vector data sources. You Create TIN From Features.can use point, line, and polygonfeatures as input data for a TIN. 2. Check the features that youSome of these input features want to use in building yourshould have z-values, though not TIN.all of the features need z-values. You can use the browseYou can create a new TIN in button beside the Layers listArcMap or ArcScene. You can to navigate to other featureuse features that are in the map classes to include in the TIN.or scene, or you can navigate to 3. Click the dropdown arrowfeature classes that aren’t on the and choose the Heightmap to include them in a TIN. source field. 2 You can choose shape 3 geometry if the features have 4 3D geometry. 5 4. Click the dropdown arrow and choose how the features should be incorporated into the TIN—as mass points, breaklines, or polygons. 7 8 5. Optionally, click the dropdown arrow and choose the Tag value field if you wish to tag the TIN features with a value from the input features. 6. Repeat steps 2 through 5 for each input feature class. 7. Type a name for the TIN. 8. Click OK.CREATING SURFACE MODELS 103
  • 110. Tip Adding features to a TINAdding the selected 1. Click 3D Analyst, point tofeatures to a TINYou can add features to refine a Create/Modify TIN, and click 1 Add Feature to TIN.TIN that has already been created,rather than re-creating the TIN 2. Check the features that youfrom scratch. If a feature class has want to add to the TIN.some features selected, only those You can use the Browsefeatures will be included in the button beside the Layers listTIN. to navigate to other feature classes to include in the TIN. 3. Click the dropdown arrow and choose the Height source field. You can choose shape geometry if the features have 2 3D geometry. 3 4. Select how the features 4 should be incorporated into 5 the TIN—as mass points, breaklines, or polygons. 5. Optionally, click the dropdown arrow and choose the Tag value field if you wish to tag the TIN features with a value from the input features. 7 6. Repeat steps 2 through 5 for each input feature class. 7. Click OK.104 USING ARCGIS 3D ANALYST
  • 111. Creating a TIN Converting a raster to a TINfrom a raster 1. Click 3D Analyst, point toYou can convert a raster surface Convert, and click Raster toto a TIN for use in surface TIN.modeling or to simplify the 2. Click the dropdown arrow andsurface model for visualization.Converting to a TIN can also click the raster that you want 1 to convert to a TIN.allow you to enhance yoursurface model by adding features 3. Type a vertical accuracy forsuch as streams and roads that the TIN.are not represented in the originalraster. 4. Optionally, check the box to 2 limit the number of pointsWhen you convert a raster to a added to the TIN in pursuit ofTIN, you need to specify the accuracy.vertical accuracy of the output 5. Optionally, type the maximumTIN with respect to the original number of points to add toraster. 3D Analyst will select the the TIN in pursuit of accuracy.subset of points needed to 3achieve this level of accuracy. 6. Type a name for the Output TIN.Tip 7. Click OK. 4What is the vertical 5accuracy?The vertical accuracy is themaximum number of units that theTIN surface may differ from thecell center heights of the inputraster. Specifying a low number 6 7results in a TIN that preservesmore of the detail of the rastersurface. A higher number willresult in a more generalizedrepresentation of the surface.CREATING SURFACE MODELS 105
  • 112. Creating a raster Converting a TIN to a rasterfrom a TIN 1. Click 3D Analyst, point toYou can convert a TIN to a raster Convert, and click TIN toto use in surface modeling or to Raster.extract slope or aspect informa- 2. Click the dropdown arrow andtion from the TIN. click the TIN that you want to convert to a raster.Tip 3. Click the Attribute dropdown 1What is the Z factor? arrow and click the attributeThe Z factor is used to convert the of the TIN that you want toz units to the same scale as the x save as a raster.and y units, if they are different. You can choose from eleva- 2 tion, aspect, slope in percent- age, and slope in degrees. The TIN must have already been symbolized by the attribute in your scene or map. 3 4. Optionally, set a Z factor. 4 5. Optionally, type the Cell size for the raster. 6. Type a name for the Output raster. 7. Click OK. 5 6 7106 USING ARCGIS 3D ANALYST
  • 113. Managing 3D dataIN THIS CHAPTER 4 ArcCatalog allows you to manage your 3D data in the same way that you manage all of your other GIS data. You can use ArcCatalog to organize your• ArcCatalog basics work—copy, paste, move, and delete 3D data in the Catalog tree using drag• Previewing 3D data and drop, commands, or shortcut keys. You can use the Preview tab to see a planimetric preview of your 3D data with the Geography option or preview it• The camera, the observer, and the in 3D using the 3D View option. You can create 3D layers of 3D and 2D target data and assign 3D viewing properties—for example, you can set the base heights and extrusion expressions for features with z-values stored in an• Displaying 2D data in 3D attribute. You can also control how a 3D layer is rendered during scene• Starting ArcScene from ArcCatalog navigation, and you can specify whether or not features are shaded based on their position relative to a light source. In addition, you can create• Creating a new 3D feature class metadata, including perspective view thumbnail graphics, for your data. 107
  • 114. ArcCatalog basicsArcCatalog lets you organize your data in an expandable tree Large Icons Thumbnailsview. You can view the selected item in the Catalog tree indifferent ways, using the tabbed view area to the right of the tree.The Contents tab lets you see the contents of an item in the tree.The Preview tab lets you see the data contained in the selected List Detailsitem. The Metadata tab lets you see the selected item’s metadata. Large Icons ThumbnailsCatalog tree and contents of a folder connectionBrowsing the Catalog’s contentsWhen you select items—for example, folders, databases, orfeature datasets—in the Catalog tree, the Contents tab lists the List Detailscontents of each item. You can expand items that contain otheritems—for example, folders—and see their contents in the tree as Use the Contents tab and the Catalog tree to browse and managewell. Items such as scene documents, maps, layers, and tables your data.don’t contain other items; when you select them in the Catalogtree, the Contents shows the name and type of the object and a Previewing datathumbnail if one has been created. Often, viewing your data in the Contents tab shows you all youYou can display the Contents list in several ways. To change its need to find the right data for a scene or map. Sometimes, though,appearance, use buttons on the Standard toolbar. you need more information. You can explore your data in the Preview tab. As with the Contents tab, you can control how you preview data.108 USING ARCGIS 3D ANALYST
  • 115. You can draw geographic data with the Geography view. You canalso examine the attributes of feature data or the contents of anyother table with the Table view. Use the dropdown list at thebottom of the Preview tab to choose how you want to preview This set of tools enables you to navigate around your data in 3D,your data. query the features in your data, and create perspective view thumbnail snapshots of your data. Using metadata Before you decide to use a data source in a map, you may want to learn more about it. Metadata is background information that lets you make better decisions about what data to use and how to use it. You can view metadata in ArcCatalog using the Metadata tab. Metadata usually contains documentary information about why the data was created, who created it, and how accurate the dataGeography and table previews—the Z in the Shape field indicates ageometry that contains z-values.3D Analyst also gives you another way to preview your data—the 3D View preview—and a new toolbar that you can add toArcCatalog to navigate the 3D preview. Metadata view is. This kind of information can be edited using a metadata editor in ArcCatalog. Metadata also contains information about the3D View preview properties of the data—for example, the attributes stored forMANAGING 3D DATA 109
  • 116. features or the coordinate system of the data. ArcCatalogautomatically maintains this information for you.You can change the way you view an item’s metadata bychoosing a different stylesheet from the dropdown list on theMetadata toolbar. Search for data with metadata containing the word elevation. When you’ve found the data you want to use, ArcCatalog lets you drag it directly onto a map or scene document or create a layer that specifies how the data should be symbolized and rendered in 2D or 3D.Metadata viewed with the FGDC FAQ stylesheetYou can also use the ArcCatalog Search tool to search for databased on information in the metadata.The Search tool dialog box contains four tabs that allow you tosearch for data that satisfies various conditions. Search110 USING ARCGIS 3D ANALYST
  • 117. Previewing 3D Navigating in 3D 1 2data 1. Click the Navigate button on the 3D View toolbar.When the selected item in the The Navigate tool allows youCatalog tree contains geo- to rotate the data in 3D, tographic data, you can preview zoom in and out, and to panthat data without having to the data.create a map or 3D Scene. For aplanimetric view of your data, 2. Click on the data and drag itchoose Geography from the to the right.Preview dropdown list on the When you click on the dataPreview tab. For a perspective and drag to the right, youview, choose 3D View. In order rotate the data counterclock-to view data in 3D, you will wise around the z-axis.need to enable the 3D Analyst 3. Right-click on the 3D dataextension. and drag down.The 3D View tools allow you to When you right-click on thenavigate around your data in data and drag down, you3D. Some of these tools are like zoom in to the data. utools that you use in ArcMapand ArcCatalog to pan andzoom in 2D. Other tools are uTipWhy does my data look flatin 3D View preview?TINs and feature classes with 3z-values embedded in theirgeometry—for example, PointZ,PolyLineZ, PolygonZ, andMultipatch shapes—will beautomatically rendered in 3D whenyou select 3D View. Rasters and 2Dfeature classes will be rendered asthough they rest on a flat surface.You can create layers that specify3D rendering properties for alltypes of data, and the layers will berendered in 3D.MANAGING 3D DATA 111
  • 118. specialized for 3D perspectiveviewing. 4. Click both mouse buttons—or the center button on a three- 4 button mouse—and drag theYou use the same tools for data to the right.navigating in ArcScene. Clicking both buttons andThe Navigate tool combines thefunctions of several of the other dragging the data pans the 5. Click on the data and dragClicking the left, right, and mouse buttons anddragging up, down, left, or right Clicking and dragging thelets you rotate the 3D view, data up lowers your viewingzoom in and out, and pan position relative to the data.across the view. 6. Click the Full Extent button.You can also use the 3D The data returns to thepreview to preview a scene original extent and viewdocument before you open it in position.ArcScene.TipSeeing the entire dataset 6If you want to see a dataset’s entirecontents after zooming andpanning around it, click the FullExtent button on the 3D Viewtoolbar. 5112 USING ARCGIS 3D ANALYST
  • 119. The camera, the Centering 1observer, and the 1. Click the Center on Target 2. Click the location that youYou view a scene through a want to occupy the center ofviewer’s camera. A camera’s the 3D view.location in a scene is defined bythe observer property. Thepoint at which the camera isdirected is called the target.When you navigate through ascene, you are actually movingthe observer in conjunctionwith the target. u 2TipWhy change the center ofthe view?By default, the center of the view isthe center of the data. The Naviga-tion tool, the Zoom In and ZoomOut tools, and the field of viewtools all change the view of the datarelative to the current center of theview. If you want to zoom in to seea particular area, centering on itfirst will prevent it from zoomingout of your field of view. Centeringon a point also allows you to rotatethe view around it.TipCentering shortcutYou can center on a target whileusing the Navigate tool. Press theCtrl key and click at the locationwhere you want to center the scene. The point you clicked is the new center of the view.MANAGING 3D DATA 113
  • 120. When you center on the cameratarget, the point you click Zooming to a target 1moves to the center of the view. 1. Click the Zoom to Target tool.When you zoom to the target, 2. Click the location that youthe view zooms to the point you want to zoom uTipZooming shortcutYou can zoom to a target whileusing the Navigate tool. Press theCtrl key and right-click to zoom toa location. 2 The view zooms in to the point you clicked.114 USING ARCGIS 3D ANALYST
  • 121. When you set the cameraobserver, the view zooms to the Setting the camera 1 observerpoint you click while pointing atthe target. You can use the Set 1. Click the Set Observer tool.Observer and the Center on 2. Click the location that youTarget tools to define how you want to zoom to.want this to happen. Anytimeyou use the Set Observer tool,the camera will point at thecurrent target. To point thecamera at a target that youchoose, use the Center onTarget tool first. Then whenyou set the camera observer, 2the camera will point toward thetarget you defined. The camera,the observer, and the target areused in the 3D view ofArcCatalog, as well as in theperspective view of ArcScene.TipSet observer shortcutYou can set the observer whileusing the Navigate tool. Press theCtrl key and middle-click to zoomto a location.TipUsing the camera tools inArcSceneThe Center on Target, Zoom toTarget, and Set Observer tools arealso available on the Navigationtoolbar in ArcScene. The view zooms to the point you clicked, honoring the target.MANAGING 3D DATA 115
  • 122. Tip Creating a 3D thumbnail 2Viewing thumbnails in the 1. Navigate the 3D view to theContents tab perspective that you’d like toIf you create a thumbnail image of show in a thumbnailyour data, it will be shown in the snapshot.Contents tab when you chooseThumbnail view. 2. Click the Create Thumbnail button. 3. Click the Metadata tab. The 3D thumbnail appears. 3 The 3D thumbnail appears in the metadata.116 USING ARCGIS 3D ANALYST
  • 123. Displaying 2D Creating a layer 1data in 3D 1. Right-click the data source from which you want to2D data can be viewed in 3D if create the create a layer and set its 3D 2. Click Create Layer.viewing properties. You canassign z-values to features 3. Navigate to the folder inbased on an attribute, a which you want to save the layer. 2constant, or an expression. Youcan also specify a surface from 4. Type a name for the layer file.which to derive the z-values of 5. Click Save.the features. The layer file is now an item3D Analyst adds three tabs to in the Catalog.the Layer Properties dialog box;these tabs allow you to modifyhow a layer is rendered in 3D.The tabs are called BaseHeights, Extrusion, andRendering. Most of the time, ifyou want to create a layer thatyou can preview in 3D, you’llset the height of the features inthe layer using the Base 5Heights tab. Sometimes youmay want to extrude features upor down from the base height—for example, if you want to 4create lines that show thedepths of well point features. Setting layer properties 1You can set how features are 1. Right-click the layer.extruded on the Extrusion tab. If 2. Click want to shade features inyour layer based on a light You can use the Layersource, you can set that Properties dialog box to setproperty of a layer from the many properties of the layerRendering tab. This tab also in addition to the 3D Base 2lets you fine-tune how your Height, Extrusion, anddata is displayed while you are Rendering properties.navigating.MANAGING 3D DATA 117
  • 124. Setting base heights 1 using an attribute 1. Click the Base Heights tab. 2. Click the option to Use a constant value or expression 2 to set heights for layer. 3 3. Click the Calculate button. 4. Double-click the field that will provide the z-value for the features. You can create an expression, such as [contour] * 3.28, to set the z-values as well. 5. Click OK. 6. Click OK on the Layer Properties dialog box. 6 The 2D features are now 4 drawn in 3D using the attribute that you selected as the z-value. 5118 USING ARCGIS 3D ANALYST
  • 125. Setting base heights 1 using a surface 1. Click the Base Heights tab. 2. Click the Browse button. 3. Navigate to a surface. 4. Click the surface. 5. Click Add. 2 6. Click OK on the Layer Properties dialog box. The 2D features are now drawn in 3D using the surface that you selected to provide the z-value. 6 4 5MANAGING 3D DATA 119
  • 126. Tip Extruding features 1What is extrusion? 1. Click the Extrusion tab.Extrusion extends featuresvertically from a given base height 2. Optionally, type a constantto the height that you specify. Points height to which all featuresbecome vertical lines, lines become will be extruded.walls, and polygons becomeblocks. 3. Optionally, click the Calculate 3 Extrusion Expression button. 4. Optionally, click the field that 2 you want to use in the extrusion expression. You can build complex extrusion 7 expressions using functions and algebraic expressions. 5. Optionally, click Load and browse to a previously saved extrusion expression. 6. Click OK. 7. Click the dropdown list to 8 choose how you want the extrusion expression applied. 4 8. Click OK. The 2D features are now extruded using the constant or expression. 5 6120 USING ARCGIS 3D ANALYST
  • 127. Starting Opening an existing 2 scene from ArcCatalogArcScene from 1. Navigate to the scene thatArcCatalog you want to open.You can start ArcScene from You can use the Preview tabArcCatalog by double-clicking and 3D View tools to previewa scene document or by clicking the scene before you open it.the Launch ArcScene button on 2. Double-click the scene in thethe 3D View Tools toolbar. Catalog tree. Opening a new scene 1 from ArcCatalog 1. Click the ArcScene button on the 3D View Tools toolbar.MANAGING 3D DATA 121
  • 128. Creating a new Creating an empty 3D 1 feature class or shapefile3D feature class 1. Right-click in the locationYou can create new empty where you want to create thefeature classes in ArcCatalog to new shapefile. Point to Newhold the 3D feature data that and click create with the 3D Analyst If you want to create ageometry interpolation tools in geodatabase feature class,ArcMap. These tools will create navigate to an existing3D graphics by default, but you geodatabase and clickcan use them while editing a 3D Feature class.feature class to create 3Dfeatures. For more information 2. Type a name for the newabout creating feature classes shapefile.and shapefiles, see Using 3. Click the Feature TypeArcCatalog. dropdown arrow and click the type (geometry) of feature that you want to create—for example, point, polyline, polygon. 4. Optionally, click Edit to define the spatial reference for the features. 2 5. Click the check box to 3 indicate that the feature coordinates will contain z-values. 6. Click OK. The shapefile is created. You can right-click it in the Catalog tree, click Properties, and add attributes if you want 4 to store attributes for the 3D features. You do not need to include a height attribute, as 5 the z-values will be stored in the feature geometry. 6122 USING ARCGIS 3D ANALYST
  • 129. Displaying surfacesIN THIS CHAPTER 5 ArcScene and ArcMap give you a wide variety of ways to symbolize and display surfaces. Because of the differences between rasters and TINs, you• Displaying raster surfaces in 3D have different options for symbolizing them.• Displaying raster surfaces You can classify the data in continuous rasters, stretch them to improve contrast, and display categorical rasters with colors to represent their• Symbolizing areas with unknown unique values. For multiband rasters, such as satellite images and some values aerial photographs, you can display the raster as a red–green–blue (RGB)• Displaying TIN surfaces composite or as a single-band stretched image. You can render cells with no data and background cells in different ways.• Making a layer transparent ArcScene and ArcMap let you show the elevation of TIN surfaces or the• Shading a layer aspect or slope of each TIN facet. You can also show the nodes and edges of the TIN in several different ways. You can make all surfaces transparent and add depth and realism to a surface by shading it based on its position relative to a light source. 123
  • 130. Displaying raster Draping a raster on a surface 1surfaces in 3D 1. In the table of contents, right-In ArcScene, you can create 3D click the raster layer that yourepresentations of raster surfaces want to drape over a surfaceby setting the base height from a and click Properties.raster or TIN surface. You can 2. Click the Base Heights tab.use this technique to visualizeterrain surfaces, show remote- 3. Click the button to Obtainsensing images in perspective, or heights for layer from surface. 3 2create abstract visualizations of If you want to use a surfaceother surface data such as other than the current rasterchemical concentrations or layer, either select one of thepopulation densities. surfaces in the scene byIf you drape a raster over a raster clicking the dropdown arrowsurface, you can change the or click the Browse buttonresolution of the base surface; the and navigate to anotherbase surface is usually resampled a lower resolution in order to 4. Click OK.increase the drawing speed. ClickRaster Resolution to set theresolution of the base surface. 4124 USING ARCGIS 3D ANALYST
  • 131. Displaying raster Drawing rasters that 3 2 4 5 represent continuoussurfaces surface data withYou can display rasters by separate classesgrouping their values into a 1. In the table of contents, right-number of classes, by stretching click the raster layer that youthe values to enhance contrast, or want to show by groupingby assigning each unique value in values into classes and clickthe raster to a color. Properties.How you display a raster depends 2. Click the Symbology tab.on the type of data that itcontains and what you want to 3. Click Some rasters have a 4. Click the Classes dropdownpredefined color scheme, but for arrow and click the number ofothers, ArcMap and ArcScene classes you want.will choose an appropriatedisplay method that you can 5. Optionally, click Classify andadjust as needed. You can change choose the classification method you want to use.display colors, group data values 7 6into classes, or stretch values to 6. Click the Color Rampincrease visual contrast. For dropdown arrow and click amultiband rasters, you can color ramp.choose three bands to display 7. Click OK.together in an RGB composite.This drawing method oftenimproves your ability todistinguish features inmultispectral images.TipWhy don’t I see the optionto use unique values?You can only draw data in integerrasters with unique values.Continuous data can be classified,drawn using a stretch, or—formultiband rasters—drawn as anRGB composite image. The continuous surface is drawn with different colors for each class.DISPLAYING SURFACES 125
  • 132. Tip Drawing rasters that 3 2Continuous rasters represent continuousMost rasters that represent surface data with asurfaces contain continuous continuous color rampvalues, whether the surface valuesrepresent elevation, temperature, 1. In the table of contents, right-or concentration of a chemical. It click the raster layer that youis often useful to display continu- want to show with a continu-ous surfaces with a continuous ous color ramp.grayscale or color ramp. The 2. Click the Symbology tab.Stretched option maps the low andhigh values in the raster to a 3. Click Stretched.0–255 intensity scale. You can 4. Optionally, click the Colorchange the way that the values are Ramp dropdown arrow andmapped by changing the type of click a color ramp.stretch used. 5. Click OK. 5 4 The continuous surface is drawn with a continuous color ramp.126 USING ARCGIS 3D ANALYST
  • 133. Tip Drawing thematic rasters 3 2 4 5Categorical rasters that represent uniqueClassifying remotely sensed categories, such as landimagery, converting vector data to coverraster, and running certainanalysis procedures can produce 1. In the table of contents, right-rasters that contain categorical click the raster layer that youvalues. In these cases, the values want to show using uniquemay be highly discontinuous and categories and clickpatchy, in comparison to the Properties.continuous and, generally, 2. Click the Symbology tab.smoothly varying values ofsurfaces. Categorical rasters are 3. Click Unique Values.usually drawn with Unique Values. 4. Click the Value Field dropdown arrow and click the field you want to map. 5. Click the Color Scheme dropdown arrow and click a color scheme. 7 6 If your raster has a colormap, click Default Colors to revert to colors specified in the colormap. 6. Optionally, click a label and type in a more descriptive name. 7. Click OK. The categorical raster is drawn with unique colors for each value.DISPLAYING SURFACES 127
  • 134. Tip Stretching a raster to 3 2 4What is a stretch? improve the visualA stretch increases the visual contrastcontrast of a raster. You mightapply a stretch when your raster 1. In the table of contents, right-appears too dark or has little click the raster layer that youcontrast. Different stretches will want to increase the visualproduce different results in the contrast of and clickraster display. You can experiment find the best one for a particular 2. Click the Symbology tab.raster. 3. Click Stretched. 4. Click the Color Ramp dropdown arrow and click a color ramp. 5. Click the Stretch Type dropdown arrow and click the stretch you want to apply. 6. Optionally, click Histogram to modify the stretch settings. 7 8 5 6 7. Optionally, if the raster contains a background or border around the data that you want to hide, check Display Background Value and set the color to No Color. The cells will display transparently. 8. Click OK. The image raster is drawn with a contrast stretch.128 USING ARCGIS 3D ANALYST
  • 135. Tip Changing the band color 3 42 5Why do I only see three assignments for abands when I added a five- multiband rasterband raster? 1. In the table of contents, right-When you add a multiband rasterto a map or scene, you see an RGB click the raster layer and clickcomposite image made from three Properties.of the bands. You can select which 2. Click the Symbology tab.three or fewer of the bands will bedrawn using the Red, Green, and 3. Click RGB Composite.Blue color elements. By default, 4. Optionally, uncheck bands tothe first three bands are mapped to turn them off.Red, Green, and Blue, but you canchange the band mapping for a 5. Click the Red, Green, andgiven image or for all images that Blue dropdown arrows andyou add. select the bands of the raster that will be displayed in red, green, and blue. 6. Click OK. 6DISPLAYING SURFACES 129
  • 136. Tip Turning bands on and offChanging band colors in a multiband rasterYou can quickly change the color 1. Click the color square besideassignments of the bands in a the band you want to turn off.multiband raster. In the table ofcontents, click the color square— 2. Click Visible to uncheck it. 1Red, Green, or Blue—and click the The band is turned off. 2band in the multiband raster thatyou want to display using thatcolor. Adding a single band of a multiband raster 1. Navigate to the raster. 2. Expand the raster to view the individual bands. 3. Select a single band and click Add. The band is added as a single-band raster. 3130 USING ARCGIS 3D ANALYST
  • 137. Setting the default color band assignments for multiband rasters 1. Click Tools and click Options. 2. Click the Raster tab. 3. Click the up and down arrows to select the bands in the 1 raster that will be rendered in Red, Green, and Blue. 2 4. Click OK. 3 4DISPLAYING SURFACES 131
  • 138. Symbolizing Setting the NoData or 2 Background display colorareas with 1. In the table of contents, right-unknown values click the raster layer and click Properties.Sometimes rasters contain cellswhere there is no measurement of 2. Click the Symbology tab.the surface. In grids these are 3. Check the box to Displayusually represented as NoData Background Value.values. In remote-sensing imagesthere are often triangular or 4. Optionally, type a value tolinear border areas within the define the raster’s Back-raster but outside the area for ground color.which image values were 5. Click the Background colorrecorded. These are often black selector dropdown arrow andand are called Background click a color—or no color.values. 6. Click the Display NoData asYou can control the way that color selector dropdownareas of NoData and Background arrow and click a color—or noare displayed. The default is to color. 3 7 4 65display NoData with no color. 7. Click OK.132 USING ARCGIS 3D ANALYST
  • 139. Displaying TIN Drawing TIN faces by 3 2 4 5 elevationsurfaces 1. In the table of contents, right-TINs are made up of triangular click the TIN.facets and the nodes and edges 2. Click the Symbology tab.that make up the triangles. Theymay also contain breaklines— 3. Click Elevation.lines that follow sets of edges 4. Optionally, click the Colorthat play important roles in Ramp dropdown arrow anddefining the shape of the click a new color ramp.surface—such as ridgelines,roads, or streams. 5. Optionally, click the Classes dropdown arrow and chooseYou can display one type of TIN the number of classes.feature in a map or scene—forexample, just the triangles—or 6. Click OK.all of the TIN features. You canalso symbolize each type offeature in different ways. 6 The TIN is drawn with different colors for each elevation class.DISPLAYING SURFACES 133
  • 140. Drawing TIN faces by 3 2 aspect 1. In the table of contents, right- click the TIN. 2. Click the Symbology tab. 3. Uncheck Elevation—or any other TIN face renderer that is checked. 4. Click Add. 5. Click Face aspect with graduated color ramp. 6. Click Add. 7. Click Dismiss. u 4 5 6 7134 USING ARCGIS 3D ANALYST
  • 141. 8. Click OK. The TIN faces are rendered with colors to indicate the direction that they face. 8 The TIN is drawn with different colors for each triangle’s aspect class.DISPLAYING SURFACES 135
  • 142. Tip Drawing TIN faces by 3 2Changing the slope of a slopeTIN surface 1. In the table of contents, right-TIN triangle slope values are click the TIN.calculated, not stored in the TIN. Ifyou change the z unit conversion 2. Click the Symbology tab.factor, the slopes of each TIN face 3. Uncheck Aspect—or anywill be recalculated. other TIN face renderer that is checked. 4. Click Add. 5. Click Face slope with graduated color ramp. 6. Click Add. 7. Click Dismiss. u 4 5 6 7136 USING ARCGIS 3D ANALYST
  • 143. 8. Click the Color Ramp dropdown arrow and select a 8 color ramp. 9. Click OK. The TIN faces are rendered with colors to indicate the slope of the terrain. 9 The TIN is drawn with graduated colors for each triangle’s slope class.DISPLAYING SURFACES 137
  • 144. Tip Drawing TIN faces by tag 3 2What are tag values? valueTIN nodes and triangles can be 1. In the table of contents, right-tagged with integer values to allow click the to store additional informationabout them. These integer values 2. Click the Symbology tab.can be used as lookup codes—for 3. Uncheck Elevation—or anyexample, to indicate the accuracy other TIN face renderer thatof the input feature data source or is checked.the land use type code for areas onthe surface. 4. Click Add.The codes can be derived from 5. Click Face tag value groupedfields in the input feature classes. with unique symbols.You can symbolize tagged featureswith unique values. 6. Click Add. 7. Click Dismiss. u 4 5 6 7138 USING ARCGIS 3D ANALYST
  • 145. 8. Click Add All Values. 9. Click OK. 8 9 The TIN is drawn with different colors for each triangle’s tag value.DISPLAYING SURFACES 139
  • 146. Tip Drawing TIN nodes by 3 2How else can I display TIN elevationnodes? 1. In the table of contents, right-You can also display TIN nodes by click the TIN.tag value or all nodes using thesame symbol. 2. Click the Symbology tab. 3. Uncheck Elevation—or any other TIN face renderer that is checked. 4. Click Add. 5. Click Node elevation with graduated color ramp. 6. Click Add. 7. Click Dismiss. u 4 5 6 7140 USING ARCGIS 3D ANALYST
  • 147. 8. Click the Color Ramp dropdown arrow and select a 8 color ramp. 9. Click OK. The TIN nodes are rendered with colors to indicate their elevation. In this example, you can also see the Soft and Hard edges, which are on by default, if the TIN has them. 9DISPLAYING SURFACES 141
  • 148. Tip Drawing TIN edges 3 4 2How else can I display TIN grouped with a uniqueedges? symbolYou can also display all TIN edgeswith the same symbol, and you can 1. In the table of contents, right-add and remove individual edge click the TIN.types from the display using the 2. Click the Symbology tab.Add Values and Remove Valuesbuttons. 3. Uncheck Elevation. 4. Click Edge types. By default, only the type 1 and 2 (Hard and Soft) edges are displayed. 5. Click Add All Values. 6. Click OK. 5 6142 USING ARCGIS 3D ANALYST
  • 149. Making a layer 1. In the table of contents, right- click the layer and click 2transparent Properties. 2. Click the Display tab.You can make raster, TIN, andfeature layers transparent in 3. Type a value in thescenes and maps. You can use Transparent box.transparent layers to visualize 4. Click that is scattered above andbelow a reference plane, comparetwo surfaces, and show terrainand subsurface features at thesame time.TipHow else can I make alayer transparent?You can use the Adjust Transpar-ency tool on the Effects toolbar inArcMap or the 3D Effects toolbarin ArcScene to set the transparencyfor a layer. 3 4DISPLAYING SURFACES 143
  • 150. Shading a layer 1. In the table of contents, right- click the layer and click 2You can shade raster, TIN, and Properties.feature layers relative to the 2. Click the Rendering tab.position of a light source in 3. Check the box to Shade arealscenes and maps. You can use features relative to theshading to increase the scene’s light position.perception of depth in the sceneand to enhance details of the The option to Use smoothtopography. shading if possible is checked by default. This minimizes the shading of small surfaceTip variations to create aChanging the light source smoother-looking shadedYou can change the light source surface.for a scene or map to enhance the 4. Click OK.shading on a surface. Click theIllumination tab on the SceneProperties or Data FrameProperties dialog box for controlsthat let you change the light source 3 4position.TipTIN face shadingYou turn shading on or off forindividual TIN face renderers byclicking the Symbology tab,clicking the TIN face rendered, andchecking or unchecking the Showhillshade illumination check box.144 USING ARCGIS 3D ANALYST
  • 151. Analyzing surfacesIN THIS CHAPTER 6 Surfaces—fields that contain an infinite number of points—typically embody a great deal of information. You may want to simply view the• Querying surface values surface, which is a great way to understand the surface in general, or you• Understanding the shape of a may be interested in specific information about parts of the surface. For surface example, you might want to know the altitude, temperature, atmospheric pressure, or concentration of a pesticide at a given point on the surface. You• Deriving slope and aspect might want to know whether an observer at point A can see point B or how information from a surface steep a proposed trail would be. You might be interested in the capacity of a proposed reservoir or the amount of material in a ridge. Or, you might be• Creating contours interested in general information about the surface’s shape that is not• Analyzing visibility immediately apparent by simply viewing the surface. For example, you may want to know what points are at the same elevation, what parts of the• Deriving hillshade from a surface surface face the same direction, and where the concentration of a chemical or the land surface declines most precipitously.• Determining height along a profile In addition to letting you view surfaces in perspective and symbolize them• Finding the steepest path in different ways, 3D Analyst gives you tools to get more information about specific points on a surface and lets you derive general information, such as• Calculating area and volume slope, aspect, and contours, from the whole surface. 3D Analyst also gives• Reclassifying your data you tools to convert surface data into vector data for analysis with other vector data sources.• Converting surfaces to vector data• Creating 3D features 145
  • 152. Querying surface Identifying features or 1 cells by clicking themvalues 1. Click the Identify button onSometimes just looking at 3D the Tools toolbar in ArcScenedata is not enough. You often or ArcMap or on the 3D Viewneed to query data or derive new Tools toolbar in to solve problems. 2. Click the mouse pointer over3D Analyst lets you explore the the feature or cell you want todata on a map or in a scene and identify.get the information you need.You can click surfaces or featuresto find out what they are. Whenyou click to get informationabout a TIN, you can find out the 2elevation, slope, and aspect ofthe point where you clicked. Ifthe TIN feature has a tag value, itwill be shown as well. When youclick a raster surface, you see theelevation value at the point.When you click a feature, yousee all of the attributes of thefeature. Displaying Map Tips for 1 surfaces 1. In the ArcMap table of contents, right-click the layer for which you want to display Map Tips and click Properties. u146 USING ARCGIS 3D ANALYST
  • 153. Tip 2. Click the Display tab. 2Displaying Map Tips for 3. Check Show Map Tips.features 4. Click OK.You can display Map Tips forfeature data layers. The Map Tip 5. Move the mouse pointer over 3shows the contents of a feature’s a TIN facet or raster cell toprimary display field. see the Map Tip.You can change the primarydisplay field by clicking the Fieldstab in the Layer Properties dialogbox, clicking the Primary displayfield dropdown arrow, thenclicking a field. 4 5ANALYZING SURFACES 147
  • 154. Understanding the shape of a surfaceOne good way to get a general understanding of the shape of asurface is to view it in 3D. You can zoom in and out and rotatethe surface to see it from different angles. When you need toshow a surface on a printed map, it can be useful to createcontour lines to represent the surface. Terrain slope and aspect surfaces. In the picture on the left, darker shades of red indicate steeper slopes. In the picture on the right, west-facing slopes are dark blue, and southeast-facing slopes are yellow. Aspect is the direction a slope faces. Aspect is often used to determine how much sun a slope will receive—for instance, to3D perspective hillshaded view of terrain and planimetric contour model how vegetation will grow, how snow will melt, or howline representation of the same area much solar heating a building will receive.3D Analyst gives you tools that let you create individual Slope and aspect in rasters and TINscontours or contours for a whole surface. An experienced mapreader can tell that the surface is steeper where the lines are close Rasters and TINs model a surface’s slope and aspect in differenttogether and identify ridgelines and streams from the shape of the ways. In a raster, slope and aspect are calculated for each cell bycontours. Contour lines can give you a feel for the shape of a fitting a plane to the z-values of each cell and its eightsurface, but they are not very useful as input for an analysis. surrounding neighbors. The slope or the aspect of the plane3D Analyst also has tools that allow for more quantitative becomes the slope or aspect value of the cell in a new raster. In aanalysis of the shape of a surface. Slope and aspect are two ways TIN, each triangle face defines a plane with a slope and anof quantifying the shape of a surface at a particular location. aspect. These values are quickly calculated, as needed, when you query or render the faces.Slope is the incline, or steepness, of a surface. It is often used inanalyses to find areas with low slopes for construction or areas Hillshading surfaceswith high slopes, which may be prone to erosion or landslides. Hillshades are the patterns of light and dark that a surface would show when illuminated from a particular angle. Hillshades are useful for increasing the perception of depth in a 3D surface and for analysis of the amount of solar radiation available at a location.148 USING ARCGIS 3D ANALYST
  • 155. There are two ways to hillshade a surface. One technique, which Deriving contour lines from rasters and TINsis most useful for adding depth for 3D visualization, is to turn onshading for the layer in ArcScene using the Rendering tab in the Contours are lines that connect all contiguous locations with theLayer Properties dialog box. This shades the layer—any surface same height—or other—value in the input grid or TIN. There areor areal 3D feature layer—on the fly, using the scene’s two ways to create contours with 3D Analyst. One way is to clickIllumination settings. Hillshading is on by default for TINs. You the surface with the contour tool. This creates a single contourmust turn it on for rasters because not all rasters are surfaces. line, which exists as a 3D graphic in a scene or map. The other way to create contours is to use the Contour surface analysis command. This creates a series of contours with a given contour interval for the whole surface. These contours are saved as a feature class with a height attribute. When you create contours from a grid, the contouring function interpolates lines between the cell centers. The lines seldom pass through the cell centers and do not follow the cell boundaries. In contrast, when you create contours from a TIN, the function interpolates straight lines across each triangle that spans the contour value, using linear interpolation between the edge3D perspective view of terrain without and with hillshading endpoints to determine where the contour crosses the face.The second technique, which is useful as input for analyses andfor enhancing depth in 2D surfaces in ArcMap, is to use theHillshade surface analysis command in the 3D Analyst toolbar.This creates a new hillshade raster that you can make partiallytransparent and display in 2D, or 3D, with an elevation layer. Contours created from a raster surface and from a TIN surface2D elevation raster, transparent hillshade raster, and shaded relief mapANALYZING SURFACES 149
  • 156. Calculating slopeWhat is slope? Elevation gridSlope identifies the steepest downhill slope for a location on asurface. Slope is calculated for each triangle in TINs and for eachcell in rasters. For a TIN this is the maximum rate of change inelevation across each triangle. For rasters it is the maximum rateof change in elevation over each cell and its eight neighbors.The slope command takes an input surface raster and calculatesan output raster containing the slope at each cell. The lower theslope value, the flatter the terrain; the higher the slope value, the Highsteeper the terrain. The output slope raster can be calculated aspercent slope or degree of slope. Low riseDegree of slope = Percent of slope = * 100 run 0–7rise θrun = tan θ 8–15 16–23 24–31 32–39Degree of slope = 30 45 76 40–47Percent of slope = 58 100 375 48–55When the slope angle equals 45 degrees, the rise is equal to the 56–63run. Expressed as a percentage, the slope of this angle is 64–70100 percent. Note that as the slope approaches vertical (90°), thepercentage slope approaches infinity. 71–78The slope function is most frequently run on an elevation grid, as Slope map (in degrees)the following diagrams show. Steeper slopes are shaded red onthe output slope map.150 USING ARCGIS 3D ANALYST
  • 157. Deriving slope Deriving slopefrom a raster 1. Click 3D Analyst, point to Surface Analysis, and clicksurface Slope.Sometimes the elevation of a 2. Select the surface from which 1point on a surface is less you want to derive a raster ofinteresting than the slope of the slope values.surface at that point. 3. Click Degree or Percent.You can derive new rasters that 4. Type a Z factor. This isshow the slope of surfaces to get calculated automatically if thethis information. input has a defined spatial 2Slope is rapidly calculated on the reference that includes z unitfly for each triangle face in a information.TIN, though you can also create 5. Type an Output cell size.rasters of slope from TINsurfaces. 6. Type the name of the Output raster. 3 7. Click OK. 4Tip 5Degree and percent slopeSlope can be measured in degrees 6from horizontal (0–90) or percentslope, which is the rise divided bythe run, times 100. As slope angleapproaches vertical (90 degrees), 7the percent slope approachesinfinity.TipWhy use a Z factor?To get accurate slope results, the zunits must be the same as the x,yunits. If they are not the same, usea Z factor to convert z units to x,yunits. For example, if your x,yunits are meters, and your z unitsare feet, you could use a Z factorof 0.3048 to convert feet to meters.ANALYZING SURFACES 151
  • 158. Calculating aspectWhat is the aspect? Why use the aspect function?Aspect is the direction that a slope faces. It identifies the steepest There are many different reasons to use the aspect function. Fordownslope direction at a location on a surface. It can be thought instance, you may want to:of as slope direction or the compass direction a hill faces. Aspect • Find all north-facing slopes on a mountain as part of a searchis calculated for each triangle in TINs and for each cell in rasters. for the best slopes for ski runs.Aspect is measured counterclockwise in degrees from 0—due • Calculate the solar illumination for each location in a regionnorth—to 360—again due north, coming full circle. The value of as part of a study to determine the diversity of life at each site.each cell in an aspect grid indicates the direction in which thecell’s slope faces. Flat slopes have no direction and are given a • Find all southerly slopes in a mountainous region to identifyvalue of -1. locations where the snow is likely to melt first, as part of a study to identify those residential locations that are likely to be hit by meltwater first. N 0 Flat • Identify areas of flat land to find an area for a plane to land in NW NE N case of emergency. 315 45 NE EW 270 90 E SE S 225 135 SW SW SE W 180 NW SThe diagram below shows an input elevation grid and the outputaspect grid. Flat N NE High E SE S Low SW W NW152 USING ARCGIS 3D ANALYST
  • 159. Deriving aspect Deriving aspectfrom a raster 1. Click 3D Analyst, point to Surface Analysis, and clicksurface Aspect. 2. Click the dropdown arrow andSometimes the elevation of apoint on a surface is less click the surface from which 1interesting than the aspect of the you want to derive a raster ofsurface at that point. aspect values.To get this information, you can 3. Type an Output cell size.derive new rasters that show the 4. Type the name of the Outputaspect of surfaces. raster. 2Aspect is rapidly calculated on 5. Click OK.the fly for each triangle face in aTIN, though you can also createrasters of aspect from TINsurfaces. 3 4 5ANALYZING SURFACES 153
  • 160. Mapping contoursWhat are contours?Contours are lines that connect points of equal value, such aselevation, temperature, precipitation, pollution, or atmosphericpressure. The distribution of the lines shows how values changeacross a surface. Where there is little change in a value, the linesare spaced farther apart. Where the value rises or falls rapidly, thelines are closer together.Why map contours?By following the line of a particular contour, you can identifywhich locations have the same value. By looking at the spacing of Feature attribute table for contoursadjacent contours, you can gain a general impression of thegradation of values.The example below shows an input elevation grid and the output Using contours in a scenecontour map. The areas where the contours are closer together Contours are a familiar surface representation for many people,indicate the steeper locations. They correspond with the areas of and they have many uses in a scene. You can display contourhigher elevation (in white on the input elevation grid). features in a 3D scene by setting the base height of the contours from their value in the feature table. Contours in a scene can enhance terrain visualization.Elevation grid and derived contour mapThe attribute table of the contour features contains an elevationattribute for each contour line. Contours superimposed on terrain surface model154 USING ARCGIS 3D ANALYST
  • 161. You can also create individual 3D graphic contour lines if you You can copy 3D contour graphics between ArcScene anddon’t want contours for the whole surface. The Contour tool on ArcMap to establish a visual correspondence between a 3Dthe 3D Analyst toolbar lets you create 3D graphic contour lines terrain representation in a scene and a 2D representation on aby clicking a surface in a scene or map. map.ArcScene 3D Analyst toolbar Contour toolArcMap 3D Analyst toolbar 3D graphic contour copied from a scene into a mapYou can use individual graphic contours to quickly find points ofequal value in a scene. For example, you can use them to markthresholds in the concentration of a chemical or fill lines in areservoir.3D graphic contours marking lines of equalelevationANALYZING SURFACES 155
  • 162. Deriving contour Deriving contourslines from a 1. Click 3D Analyst, point to Surface Analysis, and clicksurface Contour. 1Contour lines are a familiar way 2. Click the dropdown arrow andof representing surfaces on maps. click the surface from whichA contour is a line through all you want to derive contours.contiguous points with equal 3. Type the Contour interval.height or other values. While 4. Optionally, specify a Basecontours may be readily inter- contour.preted by people, they are a poorsurface model for computers. 5. Optionally, specify a Z factor.You can create contour lines for a 6. Browse to the location where 2whole surface, or you can click a you want to save the contours and type a name for them.point and create a single contourthat passes through it. 3 7. Click OK. 4Tip 5What is the offset?The offset lets you control theposition of the minimum contour.By default, the contour tool usesthe minimum Input height tocalculate the elevation for theminimum contour. If the default 6minimum contour was 298 meters,you could use an offset of 2 toplace the minimum contour at 300. 7TipWhat is the Z factor?The Z factor is used to adjust theunits of the data. For example, ifyou have data in meters, and youwant to produce contours in feet,you could use a Z factor of 3.28.156 USING ARCGIS 3D ANALYST
  • 163. Creating a single contour 1 1. Click the Contour button. 2. Click the surface at the point where you want the contour. The contour is added as a 3D polyline graphic. The height of the contour is written to the status bar. 2ANALYZING SURFACES 157
  • 164. Analyzing visibilityThe shape of a terrain surface dramatically affects what parts ofthe surface someone standing at a given point can see. What isvisible from a location is an important element in determining thevalue of real estate, the location of telecommunication towers, orthe placement of military forces. 3D Analyst allows you todetermine visibility on a surface from point to point along a givenline of sight or across the entire surface in a viewshed.What is a line of sight? Line of sight created in ArcMap and copied and pasted into a 3D sceneA line of sight is a line between two points that shows the parts of While you cannot create a line of sight in ArcScene, you canthe surface along the line that are visible to or hidden from an create one in ArcMap and copy and paste it into a scene. The lineobserver. Creating a line of sight lets you determine whether a of sight is shown in the scene as a green and red 3D line graphicgiven point is visible from another point. If the terrain hides the that follows the point, you can see where the obstruction is and what else isvisible or hidden along the line of sight. The visible segments are What is the viewshed?shown in green, and the hidden segments are shown in red. The viewshed identifies the cells in an input raster that can be seen from one or more observation points or lines. Each cell inLine of sight the output raster receives a value that indicates how many observer points can see the location. If you have only one observer point, each cell that can be seen from the observer pointObserver is given a value of 1. All cells that cannot be seen from theObserver height observer point are given a value of 0. The Observer Points feature class can contain points or lines. The nodes and vertices of lines will be used as observation points. Target Why calculate the viewshed?When you create a line of sight, you first set the offset of the The viewshed is useful when you want to know how visibleobserver and target points above the surface—the observer objects might be—for example, you may need to know “Fromshould always be set a little above the surface—then you click the which locations on the landscape will the landfill be visible if it isobserver and target points, and a graphic line appears between placed in this location?”, “What will the view be like from thisthem. road?”, or “Would this be a good place for a communications tower?”.158 USING ARCGIS 3D ANALYST
  • 165. In the example below, the viewshed from an observation point isidentified. The elevation grid displays the height of the land(darker locations represent lower elevations), and the observationpoint is marked as a green triangle. Cells in green are visible fromthe observation point, while cells in red are not visible.Displaying a hillshade underneath your elevation and the outputfrom the Viewshed function gives a very realistic impression ofthe landscape and clearly indicates the locations that an observercan see from the observation point.ANALYZING SURFACES 159
  • 166. Creating a line of 1. In ArcMap, click the Line of sight button on the 3D 1sight Analyst toolbar. 2. Optionally, type an ObserverA line of sight is a graphic line offset.between two points on a surfacethat shows where along the line 3. Optionally, type a Targetthe view is obstructed. The color offset.of the line indicates the locations 4. Optionally, check the box towhere the surface is visible andwhere the surface is hidden. The model curvature and refrac- 2 tion. For this option to bestatus bar indicates if the target is enabled, the surface must 3visible or hidden. have a defined spatialThe Line of Sight tool is only reference in projectedavailable on the 3D Analyst coordinates and definedtoolbar in ArcMap. Once you’ve z-units. 4created a line of sight in ArcMap, 5. Click the surface at theyou can copy and paste it into a observer location, then clickscene. The line of sight appears the target a scene as a 3D line thatfollows the shape of the surface,with obstructed areas shown inred and clear areas shown ingreen.TipWhat are the Observeroffset and Target offset?The Observer offset is the eye levelof the observer used in determin- 5ing what is visible from theobserver’s location. An observerwith a height of 0—the units arethe same as the surface’s z-units—will usually have a more ob-structed view than one with aheight of 1 or 10.The Target offset is the height ofthe target point above the surface.Targets with a height of 0 are lessvisible than taller ones.160 USING ARCGIS 3D ANALYST
  • 167. Deriving a Creating a map displaying the viewshedviewshed 1. Click 3D Analyst, point toThe Viewshed tool lets you find Surface Analysis, and clickthe places that can be seen from or more observation points 2. Click the Input surfaceor lines. If lines are used as input, dropdown arrow and click thethe observation points occur at input surface you want to 1the vertices of the lines. calculate the Viewshed from.The Viewshed tool creates a 3. Click the Observer pointsraster that contains cells coded toindicate whether they are visible dropdown arrow and click the feature layer to use as 2to or hidden from the observer. If observer points.there are more than one observerpoints, each visible cell in the 4. Specify a Z factor. The default is 1. The Z factor is automati-raster shows the number ofpoints from which it is visible. cally calculated if the input 3The Input surface can be a grid or surface has a spatial refer- 4TIN. ence with z-units defined. 5 5. Specify an Output cell size. 6Tip 6. Specify a name for the Output raster or leave theUsing optional parameters default to create a temporaryOptional viewshed parameters—SPOT, OFFSETA, OFFSETB, and dataset in your working 7 on—will be used if they arepresent in the feature observer 7. Click OK.attribute table. For more informa-tion, search ArcGIS Desktop Helpfor viewshed.ANALYZING SURFACES 161
  • 168. Computing hillshadeWhat is the hillshade function? Using hillshading in analysisThe hillshade function obtains the hypothetical illumination of a By modeling shadow, you can identify those cells that will be insurface by determining illumination values for each cell in an the shadow of another cell at a particular time of day. Cells thatelevation grid. It does this by evaluating the relationship between are in the shadow of another cell are coded 0; all other cells arethe position of the light source and the direction and steepness of coded with integers from 1 to 255. You can reclassify valuesthe terrain. It can greatly enhance the visualization of a surface greater than 1 to 1, producing a binary raster. In the examplefor analysis or graphical display. below, the black areas are in shadow. The azimuth is the same,By default, shadow and light are shades of gray associated with but the sun angle (altitude) has been modified.integers from 0 to 255, increasing from black to white. 0 The azimuth is the angular direction of the sun, measured from north in clockwise degrees from 0 to 360.270 90 An azimuth of 90 degrees is due east. The default is 315 degrees (NW). Sun angle: 45 degrees Sun angle: 60 degrees 180 The altitude is the slope or angle of Using hillshading for display the illumination source above the horizon. The units are in degrees, By placing an elevation grid on top of a created hillshade grid and from 0—on the horizon—to 90 making the elevation grid transparent, you obtain a very realistic degrees—overhead. The default is image of the elevation of the landscape. You can add other layers, 45 degrees. such as roads or streams, to further increase the informational content in the display. The light source of the hillshade to the left has an azimuth of 315 degrees and an altitude of 45 degrees.162 USING ARCGIS 3D ANALYST
  • 169. Deriving hillshade Creating a hillshade rasterfrom a surface 1. Click 3D Analyst, point toHillshade rasters show the Surface Analysis, and clickhypothetical illumination of a Hillshade.surface, given a specified light 2. Click the dropdown arrow andsource. Hillshades can be used toanalyze the intensity and duration click the surface from which 1 you want to derive a hillshadeof sunlight received at a location raster.on a surface. They are also usedin conjunction with elevation 3. Specify the azimuth you wishlayers to give depth to terrain to use. The default ismaps. Hillshade works on raster 315 degrees. 2and TIN layers. 4. Specify an altitude. TheYou can accentuate topographic default is 30 degrees.features by changing the altitude 5. Optionally, check Modeland azimuth values. Altitude isthe slope or angle of the illumi- shadows if you wish to 3 include the shading effect ofnation source above the horizon; surrounding cells. Cells in the 4azimuth is its angular direction. shadow of other cells will be coded 0. 5Tip 6. Specify a Z factor. The 6Modeling shadows default is 1. The Z factor is 7Check Model shadows to code automatically calculated if the input surface has a spatial 8cells 0 if they are in the shadow ofother cells. reference with z-units defined.Tip 7. Specify an Output cell size. 9Specifying a Z factor 8. Specify a name for theUse the Z factor to make the Output raster.z-value units the same as the x,y 9. Click OK.units. If your x and y units are inmeters, and your z units are in feet,you would specify a Z factor of3.28 to convert feet to meters.ANALYZING SURFACES 163
  • 170. Tip Shading a raster with aAdding depth in 2D hillshadeYou can use a hillshade raster to 1. Create a hillshade raster fromenhance the perception of depth in the surface raster that youa 2D raster representation of want to shade (see ‘Creatingterrain. TINs support colored and a hillshade raster’ in thisshaded relief directly, so you don’tneed to create a hillshade for them. chapter). 2. In the table of contents, right- click the hillshade layer and click Properties. 3. Click the Display tab. 4. Type a value in the Transpar- ent box to set the percent 2 transparency. 50% is a reasonable value. 4 3 5. Click OK. You should now see the elevation raster through the hillshade raster. 5164 USING ARCGIS 3D ANALYST
  • 171. Shading 3D Shading a raster surface in a scene 2surfaces in a 1. In ArcScene, set the basescene height of the raster to itself (see ‘Displaying rasterShading increases the realism of surfaces in 3D’ in Chapter 5).a 3D scene and improves yourability to distinguish details of 2. Right-click the raster layer inthe surface. By default, TIN the table of contents and clicksurfaces are drawn using Properties. 4 3shading, though you can turn it 3. Click the Rendering Raster surfaces can easily beshaded, too—without the need 4. Check the box to Shade arealfor creating a hillshade raster. features relative to the scene’s light position. The option to Use smooth shading if possible is checked by default. This minimizes the shading of small surface variations, which creates a smoother-looking shaded surface. 5. Click OK. 5ANALYZING SURFACES 165
  • 172. Determining 1. In ArcMap, click the Layer dropdown arrow and click the 1 2height along a surface that you want to profile.profile 2. Click the Interpolate LineProfiles show the change in button.elevation of a surface along a 3. Click the surface and digitizeline. They can help you assess a line. When you are finished,the difficulty of a trail or evaluate double-click to stop digitizing.the feasibility of placing a railline along a given route. 4. Click the Profile Graph button. 5. Optionally, to change theTip layout of the profile graph, 3Profiling a 3D line feature right-click on the title bar ofYou can also create a profile graph the profile graph and clickfor 3D line features, as well as for Properties.3D graphics. Select a 3D linefeature and click Profile Graph. 4 5166 USING ARCGIS 3D ANALYST
  • 173. Finding the 1. Click the Steepest Path tool. 1 2. Click the surface at thesteepest path location where you want the path to begin.You can evaluate runoff patternson a TIN surface model by usingthe Steepest Path tool. TheSteepest Path tool calculates thedirection a ball would take ifreleased at a given point on thesurface. The ball will take thesteepest path downhill until itreaches the perimeter of thesurface model or it reaches apit—a point all surrounding areasflow into. The result is a 3D 2graphic line added to the map orscene.You can use the Steepest Pathtool to evaluate the integrity of aTIN surface model, for example,to find paths that end unaccount-ably or meander off in a directiondifferent from runoff on theactual site. If you’re going to usethe model for runoff studies,you’ll need to correct suchanomalies.ANALYZING SURFACES 167
  • 174. 1. Click 3D Analyst, point toCalculating area Surface Analysis, and clickand volume Area and Volume. 2. Click the dropdown arrow andUse the Area and Volume click the surface for which youStatistics tool to calculate 2D want to calculate area andarea, surface area, and volume. volume statistics.All are relative to a givenreference plane. 3. Type a height for theThe 2D area of a rectangular reference plane. 1patch of surface model is simply 4. Click to calculate above orits length times its width. The below the reference plane.surface area is measured along 5. Optionally, type a Z factor tothe slope of the surface; it takes convert the z units to x,y unitsthe variation in the height of thesurface into account. Unless the if the z units of the surface 2 are not the same as thesurface is flat, the surface area x,y units. 3will always be greater than the2D area. You can compare the You will get inaccurate resultsvalues for the 2D area and if the units are not the same 4surface area to get an indication and you do not include aof the roughness or slope of the Z factor. 5surface—the larger the difference 6. Optionally, check the box tobetween the values, the rougher save the results to a text file. 8or steeper the surface. 7. Optionally, type a name forThe volume is the space—in the text file where the resultscubic map units—between the will be saved. 6surface and a reference plane set 8. Click Calculate statistics. 7at a particular height. You candetermine the volume above the The 2D area, Surface area,plane or below it, so you can and Volume will be reportedanswer questions such as “howmuch material is between the in the area below this button and optionally written to a text 91,200-foot contour and the top of file.this hill?” or “how much water You can change thecould be stored in this reservoir parameters and click theif the top of the dam is at 300 button again to repeat themeters?” calculation. 9. Click Done.168 USING ARCGIS 3D ANALYST
  • 175. Reclassifying dataWhat is reclassification? Grouping values togetherReclassifying your data simply means replacing input cell values You may want to simplify the information in a dataset. Forwith new output cell values. Reclassifying continuous data into instance, you may want to group together various types of forestcategories is an important step in the process of transforming into one forest class or group aspect values into generalsurface data into vector data for analysis. categories, such as north-facing and south-facing slopes.The input data can be any raster format. If you add a multiband You may also want to do overlay and selection on data from araster, the first band will be taken and used in the reclassification. surface—for example, finding and selecting areas that have low slope and southeast aspect. You can create the vector data for thisWhy reclassify your data? kind of polygon overlay and selection using reclassified slope and aspect rasters.There are many reasons why you might want to reclassify yourdata. Some of the most common reasons are to: Reclassifying values of a set of rasters to a common• Replace values based on new information. scale• Classify certain values together for display. Another reason to reclassify is to assign values of preference,• Classify certain values together for conversion to vector sensitivity, priority, or some similar criteria to a raster. This may format for analysis. be done on a single raster (a raster of soil type may be assigned values of 1–10 that represent degree of susceptibility to erosion)• Reclassify values to a common scale. or with several rasters to create a common scale of values.• Set specific values to NoData or to set NoData cells to a value. Setting specific values to NoData or setting NoData cells to a valueReplacing values based on new information Sometimes you want to remove specific values from yourReclassification is useful when you want to replace the values in analysis. For example, a certain land cover type may havethe input raster dataset with new values. This could be due to restrictions—such as wetlands restrictions—that mean you can’tfinding out that the value of a cell, or a number of cells, should build there. In such cases you might want to change these valuesactually be a different value. For example, this may happen if the to NoData in order to remove them from further use in an area changed over time. In other cases, you may want to change a value of NoData to be a value. For example, you might acquire new information and want to update a value of NoData with the new value.ANALYZING SURFACES 169
  • 176. Reclassifying Replacing values based on new informationyour data 1. Click the 3D AnalystThe Reclassify dialog box dropdown arrow and clickenables you to modify the values Reclassify. 1in an input dataset and save the 2. Click the Input Rasterchanges to a new output dataset. dropdown arrow and click theThere are many reasons why you raster with a value you wishmay wish to do this, including to change.replacing values based on new 3. Click the Reclass Field 2information, grouping entries, dropdown arrow and click thereclassifying values to a common field you wish to use.scale—for example, for use insuitability analysis—or setting 4. Click the new value you wishspecific values to NoData or to change and type a new 3setting NoData cells to a value. value.The Load button enables you to 5. Type the Old values entry inload a remap table that was each New values input box 4previously created by pressing for all other values to keepthe Save button and applying it to them the same in the Outputthe input raster dataset. Raster. 5The Save button enables you to 6. Optionally, click Save to savesave a remap table for later use. the remap table. 7. Specify a name for the Output Raster or leave the default toTip create a temporary dataset inReplacing NoData values your working directory.NoData values can be turned into 8. Click OK.numeric values in the same way asyou replace any value. 6 7 8TipChanging the classes ofyour old valuesClick Classify to classify your oldvalues differently.Click Unique to separate classes ofold values into unique values.170 USING ARCGIS 3D ANALYST
  • 177. Tip Grouping entriesUngrouping entries 1. Click the 3D AnalystTo ungroup entries, right-click the dropdown arrow and clickgroup and click Ungroup Entry. Reclassify. 2. Click the Input Raster 1Tip dropdown arrow and click theChanging the classes of raster whose values you wishyour old values to group.Click Classify to change the 3. Click the Reclass Fieldclassification of your old values. dropdown arrow and click the 2Click Unique to separate classes of field you wish to use.old values into unique values. 4. Click the New values you wish to group—click one, then hold down the Shift key 3 and click the next one—then right-click on Group Entries. 5. Optionally, click Save to save the remap table. 4 6. Specify a name for the Output Raster or leave the default to create a temporary dataset in your working directory. 7. Click OK. 5 6 7ANALYZING SURFACES 171
  • 178. Tip Changing the 2Changing input ranges to classification of inputunique values rangesIf your input values are split into 1. Click the 3D Analystranges and you want them to beunique values, click Unique. dropdown arrow and click 3 Reclassify. 2. Click the Input Raster 4See Also dropdown arrow and click theSee ‘Standard classification raster whose values you wishschemes’ in Using ArcMap. to reclassify. 3. Click the Reclass Field dropdown arrow and click the field you wish to use. 4. Click the Classify button. 5. Click the Method dropdown arrow and choose a classifi- cation method to use to reclassify your input data. 6. Click the Classes dropdown 6 5 arrow and choose the number of classes into which to split your input data. 7. Click OK. 8. Modify the New values for your output grid if appropriate. 9. Specify a name for the Output Raster or leave the default to create a temporary dataset in your working directory. 10. Click OK in the Reclassify dialog box. 7172 USING ARCGIS 3D ANALYST
  • 179. Tip Setting specific values to 2To change a value to NoDataNoData 1. Click the 3D AnalystYou can also type “NoData” in the dropdown arrow and clickinput box for a new value tochange an input value to NoData. Reclassify. 3 2. Click the Input Raster dropdown arrow and click the raster with values you wish to set to NoData. 4 3. Click the Reclass Field dropdown arrow and click the 5 field you wish to use. 4. Click the input boxes for the New values you wish to turn to NoData. 5. Click Delete Entries. 6. Check Change missing values to NoData. 7. Optionally, click Save to save the remap table. 8. Specify a name for the Output Raster or leave the default to create a temporary dataset in your working directory. 9. Click OK. The values you deleted will be turned to NoData in the output grid. 6 7 8 9ANALYZING SURFACES 173
  • 180. Converting rasters and TINs to vector dataWhy convert from surfaces to vectors? Raster elevationRaster and TIN surfaces may contain information that you would model withlike to use in conventional, vector-based, GIS operations. Two continuous valuessuch vector-based operations are overlay and selection by and raster converted to categorical valueslocation.Converting rasters to featuresThe general steps to convert rasters to features for analysis are: Polygon feature class created from1. Convert the raster surface data to categorical data (elevation, the raster categories slope, or aspect categories).2. Convert the categories to polygons.3. Use the polygons with other vector data and select the areas Polygon feature class that meet some criteria. of vegetation types and selectedFor example, suppose you have a raster elevation model and a vegetation that fallspolygon feature class of vegetation. within a selected elevation class polygon Raster elevation You can also use this technique to extract linear features from model and vector rasters. For example, you could extract stream courses or roads vegetation feature from land cover rasters or remotely sensed images. class. Converting TINs to featuresYou might want to select parts of a study area that are below Converting TINs to features involves fewer steps. You can extract1,000 meters in elevation and have a particular vegetation type. slope and aspect polygons directly from TIN surfaces, or you canIn order to do the vector overlay and selection with the elevation extract the elevation values of nodes in the TIN as a point featuredata, you need to convert the raster to polygons. class. You can use the slope and polygon features extracted from a TIN just as you would use such features extracted from a raster.174 USING ARCGIS 3D ANALYST
  • 181. Converting Converting raster data to featuressurfaces to vector 1. Click the 3D Analystdata dropdown arrow, point to Convert, and click Raster toYou can convert surface data to Features.vectors—point, line, or polygonfeatures—for use in selections or 2. Click the Input raster 1overlay or for editing. dropdown arrow and click the raster dataset you want toRasters must be reclassified from convert to a feature.continuous data to categoricaldata—for example, from slope in 3. Click the Field dropdowndegrees to slope categories or arrow and click the field youfrom elevation values to eleva- want to copy to the outputtion classes. features. 4. Click the Output geometry 2 type dropdown arrow and click the type of feature you 3 want to create from your 4 raster data. 5. Specify a name for Output 5 features or leave the default to create a temporary dataset in your working directory. 6. Click OK. 6ANALYZING SURFACES 175
  • 182. Converting TIN data to features 1. Click the 3D Analyst dropdown arrow, point to Convert, and click TIN to Features. 2. Click the Input TIN dropdown arrow and click the TIN you want to convert to features. 3. Click the Conversion 1 dropdown arrow and click the type of conversion that you want to do. 4. Specify a name for the Output feature or leave the default to create a temporary dataset in your working directory. 2 5. Click OK. 3 4 5176 USING ARCGIS 3D ANALYST
  • 183. Creating 3D Deriving existing features’ height from afeatures surfaceIt is often useful to have features 1. Add the 2D features and thewith 3D geometry. Although you surface to a map or scene.can display 2D features bydraping them over a surface, 3D 2. Click 3D Analyst, point to 2features are displayed more Convert, and click Featuresrapidly, and you can share them to 3D.with others without having to 3. Click the Input Featuressend along the surface data. dropdown arrow and click theYou can convert existing 2D features that you want to convert to 3D.features to 3D in three ways. Onemethod is to derive the height 4. Click the Raster or TIN 4 3values of the features from a Surface button to set thesurface. The second is to derive source for the features’the height value from an attribute heights.of the features. The third is to 5. Click the dropdown arrow andderive the features’ height from a click the surface that you 5constant value. wish to use.You can also digitize new 6. Optionally, browse to thefeatures over a surface in location where you want toArcMap and interpolate the save the output feature classfeatures’ z-values from thesurface during digitizing. or shapefile. 6 7. Type the name of the output 3D feature class or shapefile.TipCreating 3D graphics 8. Click OK. 7 8You use the same tools to digitize3D graphics from a surface as youuse to digitize 3D features. See‘Creating 3D graphics bydigitizing over a surface’. You cancopy and paste 3D graphics fromArcMap to ArcScene.ANALYZING SURFACES 177
  • 184. Tip Deriving existingGiving all of the features features’ height using anthe same z-value attributeYou can click the numeric constantbutton if you want to give all of the 1. Add the 2D features to a mapoutput 3D features the same or scene.z-value. 2. Click 3D Analyst, point to 2 Convert, and click Features to 3D. 3. Click the Input Features dropdown arrow and click the features that you want to convert to 3D. 4. Click the Input Feature 4 3 Attribute button to set the source for the features’ heights. 5. Click the attribute that you wish to use for the features’ heights. 5 6. Optionally, browse to the location where you want to save the output feature class or shapefile. 6 7. Type the name of the output 3D feature class or shapefile. 8. Click OK. 7 8178 USING ARCGIS 3D ANALYST
  • 185. Tip Creating 3D features bySelecting the surface to digitizing over a surfacesupply z-values 1. Add the 3D feature class—anIf you have more than one surface existing feature class withon the map, use the Layer one of the following geom-dropdown list on the 3D Analyst etries: pointZ, polylineZ,toolbar to select the surface that polygonZ—to which you wantwill be the source of your features’z-values. to add features to the map. 2. Add the surface that you want to use as the source for theTip features’ height to the map.3D polygon feature 3. On the Editor toolbar, clicklimitation Editor and click Start Editing.The perimeters of 3D polygons arewhere the z-values are stored. The 4. If you have more than oneinterior elevations are interpolated feature class on the map,based on these values. For identify the workspace of therelatively smooth surfaces, the feature class in which you willinteriors of 3D polygon featureswill reflect the actual surface be creating new 3D features. Click OK. 3reasonably well. If you need toaccurately model the details of an 5. Click the Interpolate Point,area, use a TIN or raster surface Interpolate Line, orinstead of polygons. Interpolate Polygon button, depending on the geometry of the feature class you are creating. 5 6. Click on the surface and create the edit sketch for the feature just as you would for a 2D feature. 6 7. When you are finished digitizing, click Editor and click Save Edits. 8. Click Editor and click Stop Editing. 9. Click Yes to save your edits.ANALYZING SURFACES 179
  • 186. Tip Creating 3D graphics bySelecting the surface to digitizing over a surfacesupply z-values 1. Add the surface that you wantIf you have more than one surface to use as the source for theon the map, use the Layer graphics’ height to the map.dropdown list on the 3D Analysttoolbar to select the surface that 2. Click the Interpolate Point,will be the source of your graphics’ Interpolate Line, or Interpo-z-values. late Polygon button, depend- ing on the geometry of the graphics you are creating.Tip 3. Click the surface at the3D polygon graphics location where you want tolimitation start drawing.The perimeters of 3D polygons arewhere the z-values are stored. The If you are using the Interpo-interior elevations are interpolated late Point tool, a point willbased on these values. For appear. 2relatively smooth surfaces, theinteriors of 3D graphic polygons If you are using the Interpo-will reflect the actual surface late Line or Interpolatereasonably well. If you need to Polygon tools, the first vertexaccurately model the details of an will appear. Click the surface 3area, use a TIN or raster surface where you want to create theinstead of polygons. next vertex. 4. Double-click the surface to create the last vertex andTip finish drawing.Using 3D graphics in 4ArcSceneYou can copy 3D graphics thatyou’ve created in ArcMap andpaste them into ArcScene.180 USING ARCGIS 3D ANALYST
  • 187. 3D visualizationIN THIS CHAPTER 7 Viewing data in three dimensions gives you new perspectives. 3D viewing can provide insights that would not be readily apparent from a planimetric• Creating a 3D scene map of the same data. For example, instead of inferring the presence of a• Adding layers and graphics to a valley from the configuration of contour lines, you can actually see the scene valley and perceive the difference in height between the valley floor and a ridge.• Defining 3D properties for layers ArcScene lets you build multilayered scenes and control how each layer in• Using the 3D Effects toolbar a scene is symbolized, positioned in 3D space, and rendered. You can also control global properties for the scene, such as the illumination. You can• Navigating through a scene using select features in a scene by using their attributes or their position relative the Fly tool to other features or by clicking individual features in the scene. You can navigate around a scene or specify the coordinates of the observer and• Setting bookmarks target for a viewer.• Viewing in Stereo mode• Defining properties of a scene• Identifying and selecting features• Managing viewers• View settings• Exporting a scene• Printing a scene 181
  • 188. Creating a new Adding data in ArcScene 1scene 1. Click the Add Data button on the ArcScene Standard 2If you start ArcScene with an toolbar.empty scene, you will probably 2. Navigate to the surface orwant to add some data to it. You feature data.can add data surfaces, 2D or 3Dfeature classes, or layers that 3. Click Add.specify how the surface orfeature data will be rendered in3D. Once you add data to ascene, you can change how thelayers of data in the scene arerendered by modifying their 3layer properties. You can alsochange general properties ofthe scene including thebackground color, the illumina-tion of the scene, and the Adding data from 1vertical exaggeration of the ArcCatalogscene. 1. Navigate to the data in the Catalog tree. 2. Click and drag it onto the scene. 2182 USING ARCGIS 3D ANALYST
  • 189. Tip Adding data fromWhy is the symbology of ArcMapmy layer different in 1. Right-click the layer in theArcScene? ArcMap table of contents andA layer file specifies how data click Copy.should be rendered in ArcMap, 1ArcCatalog, or ArcScene. The 3D 2. Click the ArcScene windowproperties that you can set for a to make it active, right-clicklayer—those found on the Base Scene layers, then clickHeights, Extrusion, and Rendering Paste Layer(s).tabs—do not apply in ArcMap.Similarly, some symbology that youcan set in ArcMap—multilayersymbols, dashed lines—will notshow up in ArcScene. Features inArcScene can be symbolized withsimple symbols and using gradu-ated symbols or colors. 23D VISUALIZATION 183
  • 190. Adding 3D Copying and pasting 3D 1 graphics from ArcMapgraphics to a 1. Click the Select Graphicsscene button on the ArcMap Tools toolbar.Once you’ve added data to a 2. Click the graphic.scene, you may find that youalso want to add a 3D graphic. 2 3. Right-click the graphic andFor example, you might have click Copy.created a single contour line; aline of sight; a steepest path; or 4. In ArcScene, click Edit and 3simple 3D point, line, or click Paste.polygon graphics with one ofthe 3D Analyst tools in Arc-Map. You can copy and pastethese 3D graphics from ArcMapinto ArcScene.184 USING ARCGIS 3D ANALYST
  • 191. Feature data and 3DYou may want to visualize feature data, as well as surfaces, in a Sometimes features lack elevation or height values. You can stillperspective view. view these features in a 3D scene by draping or extruding them. IfFeature data differs from surface data in representing discrete you have a surface model for the area, you can use the values inobjects, rather than continuous phenomena. Features typically the model as z-values for the features. This is called draping thehave a shape (geometry) and attributes. features. You can also use this technique to visualize image data in 3D. If you want to show building features in 3D, you canSome typical feature geometries are point, line, or polygon. Point extrude them using an attribute such as building height orfeatures might represent mountain peaks, telephone poles, or well number of stories. You can also extrude features based on anlocations. Lines might represent roads, streams, or ridgelines. arbitrary value.Polygons might represent buildings, lakes, or administrativeareas. The attributes of features can store values that refer to the Sometimes you’ll want to view 2D features in a scene withelevation or height of the features. Some GIS features store z-values taken from some attribute other than a height value. Forelevation values with the feature geometry itself; for example, example, you might create a scene that shows city pointsPointZ features are stored as a set of x,y,z coordinates. You can extruded into columns based on their population.use z-values in the geometry or attributes of features to displaythe features in a 3D scene. U.S. cities, height extruded based on population in 1990Building footprints extruded by building height3D VISUALIZATION 185
  • 192. Defining the Examining the base heights of a layerz-values for a 1 1. Right-click the layer and clicklayer Properties in ArcScene or ArcCatalog.When you add a layer to ascene, it may not initially be 2. Click the Base Heights tab.rendered in 3D. TINs and This layer does not have 2features with 3D geometries— base heights.for example, pointZ, polylineZ,polygonZ, and multipatchshapes—are automaticallydrawn in 3D. Rasters (grids andimages) and 2D features aredrawn as though they wereresting on a flat surface. Inorder to view rasters and 2Dfeatures in 3D, you need todefine their z-values.3D Analyst adds three tabs tothe Properties dialog box thatallow you to control how afeature layer is displayed in 3D.There are three ways to render2D features in 3D. These aresetting base heights using anattribute, setting base heightsby draping features on asurface, and extruding features.There are some variations onthese methods, and you cancombine them—for example,you can set base heights from asurface, then extrude thefeatures above or below thesurface.You can set the base heights ofraster layers using a surface ora constant value.186 USING ARCGIS 3D ANALYST
  • 193. Tip Setting the base heightUsing built-in z-values of a from an attributelayerSome feature data includes 1. Right-click the layer and click Properties. 3z-values in the feature geometry. Ifyou examine the attribute tables of 2. Click the Base Heights tab. 4these feature layers, you will see 3. Click the option to Use athat the shape field says PointZ, constant value or expressionPolylineZ, or PolygonZ. Features to set heights for features inwith 3D geometry are automati- layer.cally displayed in 3D in a sceneusing the z-values from the feature 4. Click the Calculate button.geometry. You can set the base 5. Double-click the field that willheight of these features using an provide the z-value for theattribute or a surface if you do notwish to use the built-in z-values. If then want to switch back to 6. Click OK. uusing the z-values, click the Layerfeatures have Z values. Use themfor heights. option. 5 63D VISUALIZATION 187
  • 194. 7. Click OK in the Properties dialog box. The 2D features are now drawn in 3D, using the attribute that you selected as the z-value. 7 Perspective view of contours, base heights set using the contours’ elevation attribute188 USING ARCGIS 3D ANALYST
  • 195. Setting a feature layer’s base heights using a surface 1. Right-click the layer and click Properties. 2. Click the Base Heights tab. 3. Click the option to Obtain 1 heights for layer from surface. 4. Click the dropdown list and click the surface that you want to use for the base heights. 5. Click OK. The layer is now drawn in 3D, using the surface that you selected to provide the z-values. 3 2 4 53D VISUALIZATION 189
  • 196. Extruding the features in a layer 1 1. Right-click the layer and click Properties. 2. Click the Extrusion tab. 3. Check the check box to 3 2 4 extrude the features in the layer. 4. Click the Calculate button to calculate an extrusion expression. u190 USING ARCGIS 3D ANALYST
  • 197. 5. Double-click an attribute you want to include in the 5 expression. 6. Optionally, build a calculation that includes the attribute. 7. Click OK. 8. Optionally, click the drop- down arrow to specify how the extrusion should be 6 applied. 9. Click OK. u 7 8 93D VISUALIZATION 191
  • 198. The features are extruded into 3D.192 USING ARCGIS 3D ANALYST
  • 199. Raster data and 3DRasters sometimes contain continuous surface data—when theydo, rendering them in 3D is a simple matter of setting the rasterlayer’s base height to itself. You can improve the appearance ofthe surface by setting the symbology, shading, base resolution,and—if the surface’s z-units are not equal to its x,y units—z-unitconversion factor. Aerial photo draped over a surfaceTerrain surface draped over a surface—itselfRasters often contain other kinds of discontinuous (nonsurface) Categorical raster draped over a surfacedata about an area—for example, thematic land use data, remotelysensed image data, scanned maps, or the results of surfaceanalyses—that can be mapped directly to a surface. You candisplay a nonsurface raster in 3D by draping it over a surfacemodel of the area. This can be a very effective way of visualizingthe relationship between the raster and the surface.USGS quad map draped over a surface3D VISUALIZATION 193
  • 200. Defining the 3D Setting a raster layer’s base heights using aproperties of a surfaceraster layer 1. Right-click the layer and clickWhen you add a raster layer to Properties.a scene, it is initially drawn as 2. Click the Base Heights tab.though it were resting on a flat 3. Click the option to Obtainsurface. In order to view rasters heights for layer from 3D, you need to define theirz-values. 3D Analyst adds two 4. Click the dropdown arrowtabs to the Properties dialog and click the surface that youbox that allow you to control want to use for the basehow a raster layer is displayed 3D. Rasters can be rendered 5. Optionally, click Rasterin 3D by interpolating heights Resolution to set the resolu-for the raster using values inthe raster itself, by using values tion of the base surface. 1in another (raster or TIN) 6. Click OK. usurface, or by giving the rastera constant base height. 3 2TipWhat is the RasterResolution?When you drape a raster over araster surface, the base surface is 4resampled to 256 rows by256 columns to improve perfor-mance. You can change theresolution of the base surface byclicking Raster Resolution andsetting either the cell size or thenumber of rows and columns. Asmaller number of rows andcolumns improves performance butreduces the resemblance of thebase surface to the original. 5 6194 USING ARCGIS 3D ANALYST
  • 201. The raster layer is now drawn in 3D, using the surface that you selected to provide the z-values.3D VISUALIZATION 195
  • 202. Converting Converting units 1z-units to x,y 1. Right-click the layer and click Properties.units 2. Click the Base Heights tab.Geographic data is typically 3. Click the Z Unit Conversion 2collected and represented in a dropdown arrow and clickcoordinate system that has the one of the predefined typessame x and y units. However, of conversion.when heights, depths, or If you need to apply a customelevations are recorded for conversion, click custom.features or surfaces, the z-unitsare not always the same as the 4. Optionally, if you’re using ax,y units of the coordinate custom conversion, type thesystem. For example, a set of conversion factor.well features might be stored in 5. Click OK.Universal Transverse Mercator(UTM) meters but have a well 4depth attribute in feet. In order 3to represent the wells correctlyin 3D, the z-values must beconverted to meters. Otherwise,when you extrude the wells in ascene, they will appear to bethree times as deep as theyreally are. 5196 USING ARCGIS 3D ANALYST
  • 203. Offsetting the 1. Right-click the layer and click Properties. 1heights in a layer 2. Click the Base Heights tab.You can add a constant amount 3. Type a constant value for theor calculated value to the base offset.height of a layer to raise—or 4. Optionally, click the Calculate 2lower—it relative to other button to create an expres-layers in a scene. This can be sion to define the offset.useful when creating 3Dvisualizations to ensure that a 5. Click OK.layer is visible above a surface,allow comparison of the shapesof two surfaces, or provide z-values for power lines or pipesthat have a given depth aboveor below a known surface.The offset can be relative tobase heights determined usinga constant or expression, asurface, or z-values embeddedin feature geometries. 4 3 53D VISUALIZATION 197
  • 204. Controlling when Rendering a layer only when navigation isa layer is stopped 1rendered 1. Right-click the layer and click Properties.Scenes can contain manylayers, and rendering some 2. Click the Rendering tab.layers can be quite demandingon your computer’s resources. 3. Click the option to Render 2 layer only while navigationIf you find that rendering a has stopped.particular large or complex datalayer causes navigation in a 4. Click OK.scene to be sluggish, you canset it to display only when 3navigation has ceased. Allow-ing a simpler layer to berendered during navigation canprovide landmarks to allow youto navigate accurately while thecomplex layer is not visible. 4198 USING ARCGIS 3D ANALYST
  • 205. Rendering a layer only during navigation 1 1. Right-click the layer and click Properties. 2. Click the Rendering tab. 3. Click the option to Render layer only while navigating. 2 4. Click OK. 3 43D VISUALIZATION 199
  • 206. Using the 3D Turning on the 3D Effects toolbarEffects toolbar 1. Right-click in the blank areaUsing the 3D Effects toolbar, near the menus and toolbarsyou can access a layer’s display and click 3D without opening itsproperties dialog box. Use the The 3D Effects toolbar 1 appears.3D Effects toolbar to adjust alayer’s transparency, change itsface culling, toggle its lighting,set its shading mode, or rank itsdepth priority.200 USING ARCGIS 3D ANALYST
  • 207. Using the 3D Effects toolbar to set a layer’s transparency 1 1. Click the Layer dropdown arrow and choose the layer you want to change. 2. Click the Adjust Transpar- ency button and move the slider to a value. 23D VISUALIZATION 201
  • 208. Using face Using the 3D Effects toolbar to adjust layerculling to control face culling 1the way layers 1. Click the Layer dropdownare drawn arrow and choose the layer you want to change.Face culling is a property that is 2 2. Click the Layer Face Cullingonly accessible from the 3D button and click the optionEffects toolbar. Use culling to you want to use.turn off the display of front orback faces of an areal feature or The default setting is to viewgraphic. For example, if you both sides.have data that is surrounded by 3. Optionally, click a differenta multipatch shapefile used for viewing option.a backdrop, use culling to turn View only one side of a layeroff the display of one of the to make the data inside itbackdrop faces so that you can visible.always see your data, evenwhen zoomed outside of thebackdrop extent. 3202 USING ARCGIS 3D ANALYST
  • 209. Changing a Using the 3D Effects toolbar to change alayer’s drawing layer’s drawing priority 1priority 1. Click the Layer dropdown arrow and choose the layerIf two layers occupy the same you want to change.location in 3D space, a stitchingeffect may be seen when the 2. Click on the Change Depthlayers are drawn in a scene.This is because they are Priority button and move the slider to a value. 2competing with each other to bedisplayed. To reduce the effect,assign a priority to the layersso that you control the order inwhich they are drawn. Forexample, if your scene containsa feature layer draped on asurface layer, and you notice aconflict between the layers, youcan lower the priority of thesurface so that the features arealways drawn first. Priority canonly be changed for area-basedfeatures, such as polygons,rasters, and TINs.3D VISUALIZATION 203
  • 210. Viewing a scene from different anglesBy default, ArcScene has a single window for viewing your You can navigate independently within each viewer window—thescene, but you can create multiple viewer windows for a scene. navigation tools control the view within the window they’re usedHaving additional viewers lets you focus on specific areas from in. You can even make the scene rotate in one viewer andthe best angles while still seeing the whole. navigate in another.204 USING ARCGIS 3D ANALYST
  • 211. Managing scene Adding a viewerviewers 1. Click Window and click Add Viewer. 1Multiple viewers let you see ascene from different angles atthe same time. Each viewer canbe independently navigated.You can maximize viewers to fillthe screen, minimize viewers toget them out of the way, restoreviewers to their previous size,or close them altogether.The properties of a scene applyto all of the viewers. Closing a viewer 1. Right-click the title bar of the viewer and click Close. 13D VISUALIZATION 205
  • 212. Managing viewers 1. Click Window and click Viewer Manager. 2. Click a viewer in the Select 1 viewer list. 3. Click Hide to hide the selected viewer. 4. Click Show to show the selected viewer. 5. If you have minimized a viewer, you can click Restore to restore it to its previous size. 6. Click Close Viewer(s) to permanently close the viewer. 7. Click OK to close the Viewer Manager. 2 4 3 5 6 7206 USING ARCGIS 3D ANALYST
  • 213. Changing the Setting a viewer to 2Dviewer settings 1. Click View and click View 1 Settings.You can also change the way 2. If you have more than oneyou see a scene in each viewer viewer for the scene, click thein several ways. dropdown arrow and selectYou can switch a viewer from a the viewer that you want toperspective view to an ortho- change.graphic view with no perspec- 3. Click Orthographic (2D view).tive distortion of scale. This You see an orthographic 2lets you examine the data in theview as though it were on a 2D view of the scene with nomap. perspective distortion of scale.You can change the roll angleand pitch of a viewer. 4. Click Cancel to close the View Settings dialog box.You can also change theposition of a viewer and itstarget point by typing x,y,zcoordinates.You can continue to navigate ina viewer as you view the viewersettings—the position, pitch,and roll values are updated inthe View Settings dialog boxwhen you stop navigating.TipExtruded points limitationExtruded points are not visible inorthographic view. 3 4If you need to see extruded pointdata in an orthographic view, copyand paste the layer in the scene andturn off extrusion for the copy.3D VISUALIZATION 207
  • 214. Tip Changing the roll andWhy can’t I set the roll and pitch of a viewer 1pitch? 1. Click View and click ViewRoll and pitch are only applicable perspective viewing. If you havethe viewer set to Orthographic, the 2. If you have more than onepitch and roll controls are viewer for the scene, click thedisabled. dropdown arrow and select the viewer that you want to change. 3. Click the roll slider and drag 2 it to change the roll. The artificial horizon and the viewer roll to the new roll angle. 4. Click the pitch slider and drag it to change the pitch. The artificial horizon and the viewer pitch to the new pitch angle. 5. Click Cancel to close the View Settings dialog box. 4 3 5208 USING ARCGIS 3D ANALYST
  • 215. Tip Specifying theFinding a target’s coordinates of the 1coordinates observer or targetWith the View Settings dialog boxopen, click the Center on Target 1. Click View and click Viewtool and click a location in the Settings.scene. The viewer centers on the 2. If you have more than onetarget, and you can see its x,y,z viewer for the scene, click thecoordinates. dropdown arrow and select the viewer that you want to change. 2 3. Type the x,y,z coordinates for the Observer. 4. Type the x,y,z coordinates for the Target. 5. Click Apply to set the viewer to the new observer and target coordinates. 4 6. Click Cancel to close the View Settings dialog box. 5 3 63D VISUALIZATION 209
  • 216. Navigating Using the Fly tool to navigate in a scenethrough a scene 1. Click the Fly button. 1using the Fly tool The cursor changes toUse the Fly tool to investigate indicate fly mode is active.your scene by flying through it. 2. Click once in the center of theYou can fly in any direction and scene.move forward or backward atdifferent speeds. The tool enters the sus- pended state. You can point the mouse to look in allTip directions, but there is noFine-tuning the fly speed translational movement.In between mouse clicks, press 3. Click the mouse to movearrow up or down to increase or forward.decrease speed, respectively. Right-click to move in reverse. Successive clicks in eitherTip direction increase the speed. Speed is indicated in the 2Looking up or down while status window.flyingPress Shift while flying to maintain 4. Click the opposite button toa constant elevation. You can then slow down incrementally andpoint the mouse up or down to look then those directions without Press Esc to immediately stopchanging the direction of travel. movement in either direction.210 USING ARCGIS 3D ANALYST
  • 217. Setting Creating a perspective 2 bookmarkbookmarks 1. Navigate to the perspectiveA 3D bookmark identifies a for which you want to createparticular camera perspective a bookmark.that you want to save and refer 2. Click the View menu, point to 1to later. For example, you might Bookmarks, and click Create.want to create a 3D bookmarkthat identifies a certain view of 3. Type a name for the book-a study area. That way, as you mark.navigate through your scene, 4. Click can easily return to thestudy area view by accessingthe bookmark. You can also use3D bookmarks to highlightareas in your scene you wantothers to see.The list of bookmarks applies to 3 4all viewers in a scene. If youcreate a bookmark in a viewer, itwill be added to a central listand can be applied to anyviewer. Using a perspective 1 bookmarkTip 1. Click the View menu, point toUsing bookmarks in Bookmarks, and click thesecondary viewers name of the bookmark youTo create or use a bookmark in a want to use.secondary viewer, right-click on its The bookmarked viewtitle bar and click Bookmarks. appears.3D VISUALIZATION 211
  • 218. Viewing in Stereo Viewing the display in stereo using red and blue 1mode anaglyphsStereo viewing provides added 1. Click View and click Viewdepth and realism to your 3D Settings.scenes. You can view yourscenes in stereo by using red 2. In the Applies to dropdownand blue stereo viewing menu, select the viewer youglasses, using a polarized want to view in stereo.stereo shutter for your monitor 3. Click Stereo View. 2in combination with specialized 4. Click the Method dropdowneyeglasses, or projecting the menu and click Red/Blue.images in a scene and viewingthe images with specialized The view mode changes soeyeglasses. that a red anaglyph of the scene is drawn superim-Red and Blue Anaglyph mode posed and to the right of adisplays the scene in overlap- blue anaglyph. Use red andping red and blue views. When blue stereo viewing glassesyou view these scenes with red to add more of a 3D feel toand blue stereo viewing your scene.glasses, you’ll benefit from anenhanced 3D effect. 5. Optionally, move the Eye Separation slider to the rightYou can also use a polarizing to increase the distanceshutter glass for your computer between the anaglyphs, or tomonitor and accessory glasses the left to decrease thethat you wear to view in stereo separation. 3with true color. You may need to adjust thisFinally, if you’d like to display to accommodate the distanceyour scenes in stereo projectedto an audience, you can use between your eyes or the 4 distance between you andFree mode stereo viewing to the computer screen. usend left and right images to 5independent projectors andthen view the images withspecialized glasses. u212 USING ARCGIS 3D ANALYST
  • 219. Shutter Glass mode requires a 6. Optionally, move the Parallaxquad-buffer graphics card to slider to the right to increaseaccommodate the shutter. Free the movements of scenemode requires a quad-buffer objects relative to thegraphics card with dual output observer, or left to decreasein order to project images in the relative movements.stereo. Increasing the parallax accentuates the movements of objects in the scene as you look at them. 7. Optionally, click Reverse left and right views to switch the red and blue sides of the view. 8. Click Cancel. 6 7 83D VISUALIZATION 213
  • 220. Viewing the display in stereo using a shutter 1 glass You will need to have a polarized shutter glass on your monitor and a pair of accompanying eyeglasses. 1. Click View and click View Settings. 2 2. In the Applies to dropdown menu, select the viewer you want to view in stereo. 3. Click Stereo View. 4. Click the Method dropdown menu and click Shutter glass. The view mode changes so that a polarized version of the scene is sent through the shutter. Use accessory stereo viewing glasses to view the scene in stereo. 5. Optionally, move the Eye Separation slider to the right to increase the image separation, or to the left to 3 decrease the separation. 6. Optionally, move the Parallax slider to the right to increase 4 the movements of scene objects relative to the 5 6 observer, or left to decrease the relative movements. 7. Optionally, click Reverse left and right views. 8. Click Cancel. 7 8214 USING ARCGIS 3D ANALYST
  • 221. Tip Projecting the display inFree viewing example stereo using free viewing 1For an example of how stereo You will need a graphics cardviewing is accomplished on a that supports output to twoprojection screen, visit 1. Click View and click View Settings. 2. In the Applies to dropdown menu, select the viewer you want to view in stereo. 2 3. Click Stereo View. 4. Click the Method dropdown menu and click Free. The view mode changes so that left and right views of the scene are placed side by side. You can send each view to independent projectors for display on a screen and then view the image for a stereo effect. 5. Optionally, move the Eye Separation slider to the right to increase the left and right image separation, or to the 3 left to decrease the separa- tion. 6. Optionally, move the Parallax 4 slider to the right to increase the movements of scene objects relative to the 5 6 observer, or left to decrease the relative movements. 7. Optionally, click Reverse left and right views. 8. Click Cancel. 7 83D VISUALIZATION 215
  • 222. Setting the properties of a sceneIn ArcScene, you can set certain properties—for example, verticalexaggeration, animated rotation, background color, extent, andillumination properties—that apply to the scene and all the layerswithin it. You can also add comments about the scene and set itscoordinate system. If your scene has multiple viewers, theseproperties also apply to all of the viewers. Illuminating a scene from different angles emphasizes different parts of a surface.Vertical exaggeration emphasizes variation in a surface.The background color can make visualizations more realistic.The tabs of the Scene Properties dialog box let you set thevarious global scene properties.216 USING ARCGIS 3D ANALYST
  • 223. Changing the 1. Right-click Scene layers and click Scene Properties.vertical 2. Click the General tab.exaggeration 3. Click the Vertical Exaggera- tion dropdown arrow and 1Vertical exaggeration can be click a vertical exaggerationused to emphasize subtle factor.changes in a surface. This canbe useful in creating visualiza- 4. Optionally, click Calculatetions of terrain where the From Extent to automaticallyhorizontal extent of the surface calculate an exaggerationis significantly greater than the factor based on the extent 2amount of vertical change in the and z-variation in the scene.surface. A fractional vertical 5. Click OK.exaggeration can be used toflatten surfaces or features thathave extreme vertical variation.The vertical exaggeration isapplied to all layers in a scene.You can exaggerate a singlelayer by changing its z-unit 4conversion factor. 3 53D VISUALIZATION 217
  • 224. Using animated Enabling animated rotationrotation 1. Right-click Scene layers andRotating a scene is a good wayto get an overview of its click Scene Properties. 1 2. Click the General tab.contents. You can make a scenespin around the current center 3. Check the check box towhen animated rotation is enable animated rotation.enabled. 4. Click OK.You can adjust the rotationspeed and the observation The navigate cursor has a circle around it when 2angle and zoom in and out while animated rotation is enabled.the scene rotates.TipToggling animated rotationusing shortcut keysWhile in navigation mode, you cantoggle on and off animated rotationin a specific viewer by pressingCtrl and Shift while clicking in thatviewer. 3 4218 USING ARCGIS 3D ANALYST
  • 225. Tip Starting animated 1Starting animated rotation rotationwith complex data 1. Click the Navigate buttonTo start complex data rotating, after enabling animatedpress Shift while dragging rapidly the direction you want the scene 2to rotate. The navigate cursor has a circle around it when animated rotation is enabled. 2. Click the scene, hold the mouse button down, drag to the left or right, and release the mouse button while the scene is in motion. The speed at which the scene rotates is proportional to the speed at which the mouse is moving when you release the button. Click the scene to stop the rotation. Changing the rotation speed 1. While the scene is rotating, press the Page Up key to increase the rotation speed and press the Page Down key to decrease the rotation speed.3D VISUALIZATION 219
  • 226. Changing the Setting the background colorbackground color 1. Right-click Scene layers andThe background color for click Scene Properties.scenes is white by default. Youcan change the background 2. Click the General tab. 1color to suit your visualization 3. Click the Background colorneeds. Various shades of blue dropdown arrow.can make the background 4. Click a color.appear to be a blue sky, while a 5. Optionally, click More Colors 2black background can simulatenight. to mix your own background color.You can quickly set thebackgound to one of the preset 6. Click OK.colors or mix your own color.You can also make the currentbackground color the defaultfor all new scenes. 3 4 5220 USING ARCGIS 3D ANALYST
  • 227. Setting the default background color for future scenes 1. Right-click Scene layers and click Scene Properties. 1 2. Click the General tab. 3. Check the check box to use the current color as the background in all new 2 scenes. 4. Click OK. 3 43D VISUALIZATION 221
  • 228. Changing the Setting the illumination azimuthscene 1. Right-click Scene layers andillumination click Scene Properties. 1You can set the azimuth and 2. Click the Illumination tab.altitude of the light source, as 3. Type an Azimuth for thewell as the amount of contrast, scene light source.used in rendering the illumina-tion of the scene. The illumina- 4. Click OK.tion properties for a sceneapply to all of the areal features, 2including extruded polygon andline features, in a scene.You can control whetherindividual layers are shaded byturning shading on or off on theRendering tab of the layer’sProperties dialog box. 3TipWhat is the azimuth?The azimuth is the compassdirection from which the lightsource shines on the scene.TipChanging illuminationproperties quicklyYou can click on the sun graphic inthe Azimuth and Altitude controlsand drag it where you want it, 4instead of typing values into the textboxes. The illumination previewand the values in the text boxes willchange to reflect the new position.222 USING ARCGIS 3D ANALYST
  • 229. Tip Setting the illuminationWhat is the altitude? altitudeThe altitude is the height, measured 1. Right-click Scene layers andin degrees above the horizon, fromwhich the light source shines on the click Scene Properties. 1scene. 2. Click the Illumination tab. 3. Type an altitude for the scene light source. 4. Click OK. 2 3 43D VISUALIZATION 223
  • 230. Tip Setting the illuminationWhat is the contrast? contrastThe contrast controls the amount of 1. Right-click Scene layers andshading applied to a surface. click Scene Properties. 1 2. Click the Illumination tab. 3. Type a contrast value. 4. Click OK. 2 3 4224 USING ARCGIS 3D ANALYST
  • 231. Changing the Setting the extent to a layerscene extent 1. Right-click Scene layers andReducing the extent of a scenecan be a useful way to remove click Scene Properties. 1 2. Click the Extent tab.extraneous information andincrease rendering performance. 3. Click Layer(s), click the Layer(s) dropdown arrow,By default, the extent of a scene then click the layer you wantis the combined extent of all of to define the scene extent.the layers in the scene. You canchange the extent of a scene to 4. Click OK. 2be the same as the extent of oneof the layers or set it usingspecific minimum and maximumx- and y-coordinates.Data that falls outside of the 3extent of the scene is notdisplayed. 43D VISUALIZATION 225
  • 232. Setting the extent using coordinates 1. Right-click Scene layers and click Scene Properties. 1 2. Click the Extent tab. 3. Click Custom. 4. Type minimum and maximum x and y values to define the extent of the scene. 2 5. Click OK. 3 4 5226 USING ARCGIS 3D ANALYST
  • 233. Changing the Finding out what coordinate system yourscene coordinate data is currentlysystem displayed in 1If all the data you want to 1. Right-click Scene layers anddisplay in a scene is stored in click Scene Properties.the same coordinate system— 2. Click the Coordinate Systemfor example, you’re using your tab.organization’s database—you The details of the currentcan just add it to a scene andnot consider whether the layers coordinate system are 2 displayed in the dialog box.will overlay properly; they will.If, however, you’ve collecteddata from a variety of sources,you’ll need to know whatcoordinate system each datasetuses to ensure ArcScene candisplay them together.When you add a layer to anempty scene, that layer sets thecoordinate system for thescene; you can change it later ifnecessary. As you add subse-quent layers, they are automati-cally transformed to the scene’scoordinate system as long asthere’s enough informationassociated with the layer’s datasource to determine its currentcoordinate system. If there isn’tenough information, ArcScenewill be unable to align the dataand display it correctly. In thiscase, you’ll have to supply thenecessary coordinate systeminformation yourself.ArcScene expects coordinatesystem information to be storedwith the data source. u3D VISUALIZATION 227
  • 234. For a layer in a geodatabase, Displaying data with athis information is part of the predefined coordinatelayer’s metadata. For coverages, systemshapefiles, TINs, and rasters,it’s stored on disk in a separatefile named after the data source 1. Right-click Scene layers and 1 click Scene Properties.but with a .prj file extension (for 2. Click the Coordinate Systemexample, streets.prj). These files tab.are optional files; thus you maystill need to define the coordi- 3. Double-click Predefined.nate system for one of these 4. Navigate through the folders 2data sources. You can create a until you find the coordinate.prj file with ArcCatalog. system you want and click it.If no coordinate system 5. Click OK.information is associated with adata source, ArcScene will All layers in the scene willexamine the coordinate values now be displayed with thatto see if they fall within the coordinate system.range: -180 to 180 degrees for x-values and -90 to 90 degrees fory-values. If they do, ArcSceneassumes that these are geo-graphic coordinates of latitudeand longitude. If the values are 3not in this range, ArcScenesimply treats the values asplanar x,y coordinates. 4TipChanging the coordinatesystem of a sceneChanging the coordinate system ofa scene does not alter the coordi- 5nate system of the source datacontained in it.See AlsoFor more information on coordi-nate systems, see UnderstandingMap Projections.228 USING ARCGIS 3D ANALYST
  • 235. Selecting Selecting features 1 2 interactively by clickingfeatures in a in a scenescene 1. Click the Select Features tool.There are several ways to selectfeatures in a scene. The most 2. Click the feature you want todirect way to select features is click them in the scene with The selected feature isthe Select Features tool or to them in an attribute table.When a feature is selected it ishighlighted.You can also select features bytheir attributes as well as bytheir location with respect toother features. For example, youcould select all of the polygonsthat you’ve classified as havingmoderately steep slope, thenselect all of the buildings thatare within these polygons. Changing the interactive selection methodTip 1. Click Selection, point toLearning more about Interactive Selection Method,selection and click the selectionFor more information about method you want to use.selecting features, see UsingArcMap. 13D VISUALIZATION 229
  • 236. Selecting features interactively by clicking on a table 1. Right-click the feature layer and click Open Attribute Table. 1 2. Click the row belonging to the feature you want to select. The selected feature is highlighted. 2230 USING ARCGIS 3D ANALYST
  • 237. Selecting features by their attributes 1 1. Click Selection and click Select By Attributes. 2. Click the Layer dropdown arrow and click the layer from which you want to select features. 3. Click the dropdown arrow and click the selection procedure that you want to use. 5 The default selection procedure is to create a new selection, but you can also add to, remove from, or 2 select from the current 3 selection. 4. Double-click the attribute 4 field that you want to select from. 5. Click an operator, for ex- 6 ample, the equals sign. 6. Double-click a value. 7. Optionally, click Verify to check your selection expression. 8. Click Apply. 9. Click Close. The features are selected. 7 8 93D VISUALIZATION 231
  • 238. Selecting features by their location 1. Click Selection and click 1 Select By Location. 2. Click the dropdown arrow and click a selection method. 3. Check the layers whose features you would like to select. 4. Click the dropdown arrow and click a selection method. 5. Click the dropdown arrow and click the layer you want to use to search for the features. 2 6. Optionally, check to use only 3 the selected features. 7. Optionally, check Apply a buffer to the features in 4 <layer> and set the distance within which to search for 5 features. 6 8. Click Apply. 7 9. Click Close. The features are selected. 8 9232 USING ARCGIS 3D ANALYST
  • 239. Exporting a Exporting a 2D graphic of a scenescene 1. Click File, point to ExportYou can export a 2D image of a Scene, and click 2D.scene to a graphics file, or you 2. Navigate to the locationcan export a 3D Virtual Reality where you want to save theModeling Language (VRML) image of the scene.model. Images of scenes can besaved in several common file 3. Click the dropdown arrow toformats and placed in other choose the graphics file format to export. 1documents—for example, inmaps or reports. 4. Type the width of the ex- ported graphic in pixels.Tip 5. Type a name for the graphic. 2Taking a snapshot of a 6. Click Export.scene The scene is exported to aSometimes you just need a quick 2D image.snapshot of a scene. Click Edit andclick Copy scene to clipboard. Youcan then paste the snapshot onto amap or other document. 6 4 5 33D VISUALIZATION 233
  • 240. Exporting a 3D VRML model of a scene 1. Click File, point to Export Scene, and click 3D. 2. Navigate to the location where you want to save the VRML model. 3. Type a name for the VRML file. 4. Click Export. 1 The scene is exported to a VRML file. 2 4 3234 USING ARCGIS 3D ANALYST
  • 241. Printing a scene 1. Click the Print button. 1 2. Optionally, click Setup.When you want a hardcopy of 3. Optionally, click the drop-a scene, you can print one. You down arrow to select acan quickly print to your default printer.printer, or you can change thepage setup to select another 4. Optionally, click the drop-printer and specify the details down arrow to select a page 2of how you want the scene to size.print. 5. Optionally, click Portrait or Landscape to select the page orientation. 6. Optionally, click the drop- down arrow to select a printer engine. 7. Optionally, click OK. 8. Click OK on the Print dialog box. 8 3 4 5 6 73D VISUALIZATION 235
  • 242. AnimationIN THIS CHAPTER 8 Animations make your 3D documents come alive by storing actions so they can be replayed as you choose. They can help you visualize changes in• 3D animation perspective, changes in the document’s properties, geographical movements, and temporal changes.• Creating animations You might create an animation that helps you visualize how moving satellites• Capturing perspective views react with one another during their orbit. In addition, you may model the earth’s rotation and change in lighting at the same time.• Recording and playing back You create animations using the Animation toolbar. You can make animations animation tracks that manipulate data, perspective, and scenes or globes.• Creating keyframes An animation consists of one or more tracks. Tracks control dynamic changes of the properties of an object, such as a document’s background• Making group animations color, a layer’s visibility, or a camera’s location. Tracks are made up of a set of keyframes. A keyframe is a snapshot of a particular object’s properties at• Making animations from paths a certain time. The object can be a scene or globe, a layer, or a camera. For example, you can create a track with the scene or globe object that animates• Using the Animation Manager scene or globe property keyframes to show the background color changing from white to black.• Timing properties in the Animation Manager Animation tracks are stored in the current document. They can also be saved into a separate file that may be shared by numerous scene• Saving an animation documents. An animation may also be exported as an Audio Video Interleave (.avi) or QuickTime (.mov) file that can be played by third party• Sharing animations: Loading an video players. ArcScene or ArcGlobe Animation file Animations provide a new and actuated aspect to your 3D documents. Use animations to automate the processes you would undertake to demonstrate points that can only be made through visual dynamics. 237
  • 243. 3D animationArcScene and ArcGlobe let you create, save, and shareanimations. You can create animations in different ways,composing the animation of multiple tracks that animate the sceneor globe properties, a layer, or the camera. An animation may besaved in a document, saved as an independent ArcSceneAnimation (.asa) or ArcGlobe Animation (.aga) file, or exported toa .avi or .mov file. You can share animations by exchangingdocuments, interchanging .asa and .aga files, or distributing .aviand .mov files.The camera and the targetYou view your scene or globe through viewer cameras. Acamera’s location is defined by the observer property. The centerof your view is called the target. Imagine what you see is what thecamera sees. As you navigate through a 3D view, you are actuallymoving the observer in conjunction with the target. If you set anew target on the data, that point on the data is shifted to thecenter of your view. There is only one camera, observer, and Creating an animationtarget set in any viewer. Familiarizing yourself with the camera, You create an animation by composing the tracks it will, and target will help you gain a better understanding of You can make tracks by creating a set of keyframes, recordinganimation. actions, alternating the visibility of groups of layers, and importing paths that constrain movement. Use the AnimationIntroducing the Animation toolbar Manager to edit tracks and keyframes and organize how theThe Animation toolbar has all the tools you’ll need to work with tracks in an animation interact with each other.animations in ArcScene and ArcGlobe. Using these tools, you canrecord navigation, capture perspective views, save and export Saving an animationtracks, create video files, make group animations, create tracks There are three ways to save an animation. A 3D document willfrom paths, and manage and preview your animations. automatically store an animation that is present when the document is saved. In addition, you can save the animation tracks to a .asa or .aga file. Finally, you can create a standalone video by exporting the animation as a .avi or .mov file.238 USING ARCGIS 3D ANALYST
  • 244. Sharing animationsYou can share animations by loading a 3D document thatcontains an animation, loading .asa or .aga files into ArcScene orArcGlobe, and viewing .avi or .mov files that were created fromanimations. Use a shared document with an animation todemonstrate a particular point to colleagues. Independent .asaand .aga files can be used as templates for others to build on oras generic animations that can be utilized with various data. Sharea .avi or .mov file for picture-perfect, highly detailed animationsthat can be played in real time to a wide and varied audiencewhen you need to quickly demonstrate a problem that can onlybe shown dynamically.ANIMATION 239
  • 245. Creating Turning on the Animation toolbaranimations 1. Click View, point to Toolbars,There are several ways to create and click Animation.animations. The simplest The Animation toolbarmethod, capturing perspective appears as an undockedviews, is quick and can be done toolbar.with any data. A more complexmethod of creating animationsis to create animations frompaths defined by selected linefeatures or graphics. Thismethod requires specific typesof data in the scene but canprovide a more visually 1appealing animation.240 USING ARCGIS 3D ANALYST
  • 246. Capturing Capturing views to make an animationperspectiveviews 1. Navigate to the perspective you want to capture. 2Use the Capture View command 2. Click the Capture View button. 1to save perspective views askeyframes in a camera track. 3. Repeat to capture moreThe resulting track will be an views as keyframes in ainterpolation between the camera track.keyframes, making a smoothanimation. For example, you cancreate a track that rotates yourscene or globe, zooming in andout to points of interest alongthe way.TipIs there a shortcut tocapturing views?To capture a view to an animation,press Ctrl+A instead of clicking theCapture View button. Clearing an animation 1. Click Animation and clickSee Also Clear Animation. 1 All animation tracks areTo learn how to play back ananimation track, see ‘Recording removed from the scene.and playing back animation tracks’in this chapter.ANIMATION 241
  • 247. Recording and Recording navigation to create an animationplaying back 1 1. Click the Open Animationanimation tracks Controls button.Simple recording and playback 2. Click the Record button.are achieved using controls thatresemble a VCR. Press the 3. Navigate in the scene using 3 any navigation tool.Record button to record yournavigation and press the Play 4. Click the Stop button.button to play it back. A camera track is created, storing the navigation sequence.Tip 4 2Recording Fly or Walk toolnavigationYou can make a flyby or walk-through animation by recording asyou fly or walk through your scene Playing back anor globe with the Fly and Walk animationtools. 1 1. Click the Open Animation Controls button.Tip 2. Press the Play button.Controlling playback and The animation is playedrecording options back.Click Options on the AnimationControls toolbar to accessanimation duration, segments of 2animation to play back, loopingmode, and overwriting options.242 USING ARCGIS 3D ANALYST
  • 248. Creating Creating a keyframe of scene propertieskeyframes 1. Right-click Scene layers andKeyframes are the most click Scene Properties.fundamental elements of an 2animation. A series of keyframes 2. Set the scene property or 1 properties you want tois assembled into a track. Create capture.a keyframe to make a snapshotof an object’s properties. Use 3. Turn on the Animationkeyframes to make snapshots of toolbar, click Animation, andscene or globe properties, click Create properties, or layer 4. Click the Type dropdownproperties, such as a 3D view’sbackground color, a layer’s arrow and choose Scene. 3transparency, or a camera’s 5. Click New to create a newlocation. scene track. 6. Click OK.TipHow can I edit keyframe 7. Click 8. Click Close.You can edit the properties of a You can repeatedly change akeyframe by using the Animation property and create a newManager. keyframe without closing the Create Animation Keyframe dialog box. Note that you 4 need at least two keyframes to create a track that will show change. 6 5 7 8ANIMATION 243
  • 249. Tip Creating a keyframe ofHow else can I create a camera propertieskeyframe? 1. Navigate to the cameraYou can create keyframes from the position you want to capture.Keyframes page of the AnimationManager dialog box. Click Create 2. Click Animation and click 1to invoke the Create Animation Create Keyframe.Keyframe dialog box. For more 3. Click the Type dropdowninformation, see ‘Using the arrow and choose Camera.Animation Manager’. 4. Click New.Tip 5. Click OK.Using bookmarks as 6. Click Create.keyframes 7. Click Close.If your document has bookmarks,you can import them to an You can change a camera property by navigating to aanimation as keyframes bychecking Import from bookmarks new position, then create a 2and choosing a bookmark in the new keyframe repeatedlydropdown list. without closing the Create Animation Keyframe dialog box. Note that you need at least two keyframes to create a track that will show change. 3 5 4 6 7244 USING ARCGIS 3D ANALYST
  • 250. Creating a keyframe of layer properties 1. Change the layer property that you want to capture. 1 For example, turn on the 3D Effects toolbar and set a transparency for a layer. 2. Click Animation and click Create Keyframe. 3. Click the Type dropdown arrow and choose Layer. 2 4. Click New. 5. Click OK. 6. Click Create. 7. Click Close. You can repeatedly change a property and create a new keyframe without closing the Create Animation Keyframe dialog box. Note that you 3 need at least two keyframes to create a track that will show change. 5 4 6 7ANIMATION 245
  • 251. Making group Making a group animationanimations 1. Click the Add Data button to 1You can create an animation add the layers or group layerfrom an existing group layer or that you want to animate.individual layers within a scene. 2. Click Animation and clickFor example, you might have a Create Group layer in which individuallayers represent snapshots in 3. Optionally, choose a Basetime. If these layers are ordered name for tracks. 2sequentially in the TOC, you You are provided with acan create tracks that succes- default name for the tracks,sively turn visibility on and off but you can change it tofor each layer within the group. something more meaningful.The animation will depend onthe ordering in the TOC, so 4. Optionally, set the beginningarrange layers in the order that and ending want them played. The Setting these times allowstracks will show how the data you to determine when thechanges through time. group animation will play relative to other tracks that 3 may exist. 5 5. Select a group layer. You can 4 click a group layer or all the layers in your scene. 6 6. Optionally, change Transitions. These options will help you determine how layers in an 7 animation change from one to another. 7. Optionally, uncheck Over- write existing tracks with 8 same name to add additional group animations. 8. Click OK.246 USING ARCGIS 3D ANALYST
  • 252. Making Making a camera flyby from a pathanimations frompaths 1. Click a selection tool and select the line feature or 1 graphic you want to use as aYou can create camera tracks path.and layer tracks from paths. Apath is defined by a selected 2. Click Animation and clickline feature or graphic, and its Camera Flyby from Path.purpose is to constrain move- 3. Optionally, check Apply inment along the selection. A reverse track is created by 2moving the camera along the The camera will begin at theselected path. A layer track is other end of the path.made by moving a layer along a 4. Optionally, type a value in thepath. Vertical offset text box.Use the Path destination An offset defines the heightoptions for a camera flyby path of the modify the way the camera 5. Optionally, slide the(observer) travels. There are simplification factor.three options for moving acamera along a path: move both The simplification factorthe target and observer along determines how much thethe path for a flyby, move the path will be generalized forobserver along the path with the animation. 3the current target to point the 6. Optionally, choose a path 4camera at an area while it u destination. 5 Change the path destinationTip to determine how theModifying camera observer and target are 6properties positioned during theWhen selecting flyby mode as the animation.path destination, click OrientationSettings in the Camera Flyby from 7. Optionally, uncheck Over- 7 write last imported track.Path dialog box to modify the waycamera azimuth, inclination, and Disabling this option willroll properties are calculated from allow you to add tracks tothe path. previous ones. 8 8. Click Import.ANIMATION 247
  • 253. moves along the path, or move Moving a layer along athe target along the path with paththe current observer to let thecamera follow a virtual point 1. Click a selection tool and select the line feature or 1along the path in the track. Youcan then move a layer along graphic you want to use as athis path to have the camera path.point toward the layer as it 2. Click Animation and clickmoves. Move Layer along Path. 3. Click the Layer dropdownTip arrow and choose the layerUsing advanced layer you want to move.orientation settings 2 4. Optionally, check Apply inClick Orientation Settings to modify reverse order.the way a layer’s azimuth, inclina-tion, and roll properties are This option will start the layercalculated from the path. moving from the opposite end of the path. 5. Optionally, type a value in the Vertical offset text box. The vertical offset determines 3 the height of the layer. 6. Optionally, slide the simplification factor. 4 The simplification factor 5 indicates how much the path will be generalized when it is 6 used for the animation. 7. Optionally, uncheck Over- write last imported track. Disable this to allow addi- tional layer tracks to be 7 imported without overwriting existing ones. 8. Click Import. 8248 USING ARCGIS 3D ANALYST
  • 254. Using the Using the Animation Manager to accessAnimation keyframe propertiesManager 1. Click Animation and click Animation Manager.The Animation Manager allowsyou to access properties of 2. Click the Keyframes tab.keyframes and tracks. In 3. Click the Keyframes of Typeaddition, you can access timing dropdown arrow and chooseproperties and preview your the type of keyframe youanimation. You can manipulatethese properties, then see the want to examine. 1result using the Time View 4. Click the In Track dropdownpreview. arrow and choose the specific track you want to 3 4 access.Tip 5. Click a Keyframe property to 2Why change a track or change it.keyframe property? 6. Press Enter.Use the Animation Manager tomodify the properties of a keyframe 7. Click Close.or track. For example, you canchange the camera target’sx-coordinate to move the target to amore pleasing position. Options tochange properties are numerous,allowing you to make your 5 7animation look just as you intend.TipUpdating a keyframeTo fine-tune a scene or camerakeyframe in the AnimationManager, select the keyframe youwant to change in the Keyframespage, modify the property in thescene, and click Update. Thekeyframe will be updated to reflectthe change.ANIMATION 249
  • 255. Tip Using the AnimationChanging a track’s priority Manager to access trackIf multiple camera or scene tracks propertiesrefer to the same object, they willbe played back according to their 1. Click Animation and clickpriority. To change a track’s Animation Manager.priority, select the track in the 2. Click the Tracks tab.Tracks page of the AnimationManager and use the arrow up or 3. Optionally, check View onlydown buttons to move its ranking. tracks of type, click theIf multiple layer tracks refer to the dropdown arrow, and selectsame layer, their transformations the type you want to 1will be combined. examine. 4. Click a Track property to 2Tip change it.What is binding? 5. Press Enter.Tracks are bound to objects. For 6. Click Close. 3example, a camera track is boundto a particular viewer, and it willplay in that viewer. To change theobject that the track is bound to,click Binding.TipCan I interact with an 4 6animation track?You can manually alter propertiesof a track to allow you, forexample, to navigate duringanimation. Select a track and clickProperties to see those that areavailable for that track. Uncheckthe ones you want to controlmanually.250 USING ARCGIS 3D ANALYST
  • 256. Timing properties Using the Animation Manager to modify timingin the Animation properties of tracksManager 1. Click Animation and clickUse the Time View page of the Animation Manager.Animation Manager to modify 2. Click the Time View tab.when keyframes of one track areplayed relative to others or to 3. Optionally, click the Plus ororganize how tracks are Minus buttons to change thesynchronized with one another. time scale.When in the Time View page, Reducing the time scale 1the timing of all tracks is gives you a more detailednormalized to one time unit, and view.there is no indication ofduration. Use the duration 4. Optionally, check View 2 4setting in the Animation Control enabled tracks only.options dialog box to determine Using this option shows onlyhow long your animation will the tracks that are currently 3play. enabled. Disable a track in the Tracks page.Tip 5. Click and drag a greenPreviewing an animation keyframe box in a track toIn the Time View page, you can change the time when it willexamine your animation by clicking be played.the display until a vertical red lineappears, then dragging the line to Moving a keyframe to a laterpreview the way your animation point in the track will cause it 5 6will play. to be played later in the animation.Tip Click and drag a keyframe at the start or end of a track toWhy are my layer tracks determine when that trackcolored differently? will play relative to others.In the Time View page, group layertracks are color-coded to indicate 6. Click Close.their visibility. Light green meansthe layer is visible; red indicatesthat the layer is invisible; and paleyellow lets you know that the layeris semitransparent, or intransitional visibility.ANIMATION 251
  • 257. Saving an Saving an animation in a scene documentanimationAn animation that is created in 1. Click the Save button. 1 An existing scene documenta scene or globe will be stored will be appended with thein the document when it’s animation, or if none exists,saved. Animation tracks can you will be prompted toalso be saved into an indepen- provide a name for a newdent .asa or .aga file. Another document that will containway to save an animation is to the animation.export it to a .avi or Quick file.In order to be able to videos, you’ll need tohave Quick Time installed onyour computer. Saving an animation by exporting tracks to an ArcScene Track file 1. Click Animation and click Save Animation File. 2. Click the Save in dropdown arrow and choose a location. 3. In the File name text box, 1 type the name you want to give the animation file. 2 4. Click Save. 3 4252 USING ARCGIS 3D ANALYST
  • 258. Tip Exporting an animationUsing advanced video to a video fileoptions 1. Click Animation and clickTo access frame rate and video Export to Video.quality properties, click Options onthe Video Export dialog box. 2. Click the Save in dropdown arrow and choose a location.Tip 3. In the File name text box, type the name of the videoPreventing extraneouswindows from appearing in file you want to create. 1video files 4. Click the Save as typeMake sure that when you export dropdown arrow and select the type of video file youyour animation to a video file youmove other windows away so want to create. 2nothing obscures the viewer that is You can export a .avi or .mov.playing the animation. Otherwise,they may appear in the exported 5. Click Export.file. A video file of the given name and type is created in the specified location. 3 5 4ANIMATION 253
  • 259. Sharing Loading an ArcScene Animation fileanimations: 1. Click Animation and clickLoading an Load Animation File.ArcScene or 2. Browse to the ArcScene Animation file you want toArcGlobe load. 1Animation file 3. Click Open.You can load an ArcScene orArcGlobe Animation file intoany scene or globe. However,when attempting to load an 2animation into a new document,care must be taken to ensurethat the animation applies to thedocument. If an animation trackrefers to an item that doesn’tapply to the document, thetrack will not play. For example,if you’ve created an animationcontaining a track that refers toa certain layer in a document, 2 3that layer must be present in thenew document and must be inthe same location in the TOC.Because a layer track refers to alayer by noting its ranking inthe TOC, the track may animatean incorrect layer or may not uTipIdentifying ArcSceneAnimation filesArcScene track files are appendedwith the .asa extension. ArcGlobetrack files are appended with the.aga extension.254 USING ARCGIS 3D ANALYST
  • 260. be enabled to play if the rankingin the new document’s TOC isdifferent. Also, if a track refersto a viewer that doesn’t exist inthe new document, that trackwill not play. In addition, ifyou’ve created a camera track ina document’s extent and wantto play it in a new document,make sure the extent of the new3D view is the same, or elseyour track might move thecamera in an area where there isno data. This is because acamera track is defined in partby a document’s extent.TipUsing animations stored ina scene or globe documentLoad the document with animationinto ArcScene or ArcGlobe as youwould any other document. Modifythe name you give to animateddocuments to let others know thatthey contain animation.ANIMATION 255
  • 261. 3D symbologyIN THIS CHAPTER 9 Using 3D symbology allows you to provide a sense of realism to your 3D documents or render cartographic symbols in 3D. You can use 3D symbols to• What is a 3D symbol? display features as 3D objects or display your map symbols in 3D.• Using 3D symbols For example, instead of symbolizing a house as a simple point, you could• Using 3D styles choose to symbolize it with a 3D model of a particular style of home, providing realism to your document. Or, you might choose to display a layer of• Making 3D symbols recreation use symbols by selecting 3D versions of the symbols for a more• The 3D Symbol Property Editor vivid effect. In addition, you could symbolize a roads layer as textured strips creating a realistic road network. Finally, you might add a texture to a surface• Altering the 3D placement of a symbol to provide a realistic ground surface to your scene or globe.• Offsetting a 3D symbol 3D symbology lets you create documents that dramatically enliven your data and provide stunning representations of your 2D maps. Using 3D symbology• Scaling the size of 3D symbols allows you to depict real-world scenarios that can be as geospecific, or• Using 3D styles to assign symbology “visually true”, as you dictate while also giving you the option to portray your data geotypically, or “stylistically true”. You’ll be able to import your existing• Symbolizing points with 3D symbols OpenFlight (.flt), 3ds max* (.3ds), or Virtual Reality Markup Language• Symbolizing lines with 3D symbols (VRML*) models into ArcGIS, then symbolize features with these models, or choose to select symbology from a rich set of included 3D styles that contain• Symbolizing polygon fills with 3D models, cartographic symbols, and 3D geometric shapes. symbols• Saving the current styles• Organizing 3D style contents• Creating and modifying 3D symbols and elements 257
  • 262. What is a 3D symbol?A 3D symbol is a 2D symbol with extended properties. Theseproperties enhance 2D symbols so that they can be viewed in 3Din an ArcGIS 3D application.While a 2D symbol has dimensions in the x and y directions, a 3Dsymbol has the additional property of a dimension in the z Existing points, on the left, symbolized by 3D model houses, on the rightdirection. Thus, a 2D point symbol is analogous to a 3D spheresymbol, a square-shaped 2D symbol is analogous to a cube- Types of 3D symbolsshaped 3D symbol, and a 2D line symbol can be analogous to a A point can be symbolized in 3D by a simple 3D marker such as atube-shaped 3D symbol. cube or a cone, a 3D character marker based on a system font, or a 3D marker as imported from a 3D model. A line can be symbolized in 3D by using a 3D simple line symbol, such as a tube or a strip; or a texture line symbol, such as a texture symbolizing a road. A polygon or surface can be symbolized by using a 3D texture fill symbol, for example, a texture resembling a geotypical feature such as grass. These options allow you toExample of 2D features on the left and the analogous 3D representationson the right3D symbols can also be more complex than simple geometricshapes. A 2D picture fill symbol, whose pattern is applied as a fillto a 2D polygon, is analogous to a 3D texture fill symbol. A 3Dtexture fill symbol is a picture fill symbol that has awareness ofits real-world size, and can be mapped on to a geometry withproper scaling. Points may also be symbolized by representationsof real-world objects (3D models) as, for example, a set of pointsindicating dwelling locations being symbolized by existing 3D 3D symbols used to portray realismmodels of houses.258 USING ARCGIS 3D ANALYST
  • 263. render realistic 3D worlds. For example, you may have an existingdocument that could be made more visually realistic bysymbolizing points representing a housing tract by 3D models ofhouses, then symbolizing the roads in this tract by using atextured line symbol that models pavement. In addition, youmight use a grass texture to symbolize a polygon feature classshowing city parks.3D SYMBOLOGY 259
  • 264. Using 3D symbolsMaking geotypical documents render font-based characters in 3D. You can use these 3D representations to bring new perspectives to your maps.A geotypical symbol is a model with realistic properties that areused to portray a certain style. A set of geotypical models mightshow a generic style or theme, such as “Capecod Houses”, withdifferent properties such as “1 story” or “2 story”. 3D Analystcomes with 3D styles that let you symbolize points, lines, andpolygons with generic 3D symbols such as typical houses,textured roads, and fills. You can use these symbols to createrealism, while still being abstract enough to not imply specific,actual objects. Use geotypical symbols to model a proposed 2D representation (left) and 3D representation of a weather maphousing tract or in existing areas where it isn’t necessary to showreal-world objects. Using geotypical 3D symbols, you can makedocuments that mimic real-world characteristics but don’t implyvisual truth.Making geospecific documentsA geospecific symbol is a model that is based on a real-worldobject. An example is a model of the White House in Washington,D.C. You can symbolize features with objects that are based onreal-world objects. For example, if you have existing 3D models ofbuildings that exist in an area, you can import them, then renderyour point feature class with the objects you’ve imported. Youcan also import any textures that you may have, such asvegetation or wall textures. You can import these models intostyles or as needed to symbolize features independent from astyle.Making 3D mapsYou can create dramatic maps that are rendered with 3Dsymbology. These maps may use a map’s 2D symbology as aguide, then display the symbols in 3D. For example, points can bedisplayed as spheres, lines as strips, and polygons as texturedobjects. In addition, you might choose a 3D character marker to260 USING ARCGIS 3D ANALYST
  • 265. Using 3D styles3D styles point feature classes. You can also symbolize points as models such as houses, vehicles, or street furniture.Styles are sets of particular symbols with preset characteristics.These symbols are categorized thematically, then saved withproperties, such as size and color, that make it convenient to usethem. 3D styles work the same way as 2D styles but contain 3Dsymbols commonly used in 3D Analyst. They may, in addition,store some real-world information about their sizing.3D Analyst comes to you with 3D styles that are ready to use.These styles contain both simple geometric shapes as well asgeotypical models. In addition, you can create your own symbols,then make your own styles containing these symbols. You canalso construct styles from existing symbols.Styles are a convenient way of storing symbology that you Example of 3D styles available for point feature classescommonly use. 3D Analyst provides styles that help yousymbolize common scenarios and also provides the flexibility foryou to create your own styles by making them from existing 3D line stylessymbols or importing them. Similarly, styles are available for line symbology. You can chooseSee ‘Working with styles and symbols’ in Using ArcGIS ArcMap from styles that contain simple geometries, such as tubes orfor more detailed information on working with styles and the Style strips, or styles that include textures of fences, walls, roads, andManager. walkways. Use 3D line styles to show roadways or fences. You might also3D point styles show a sewer network or pipe workings symbolized as tubes.When you open the symbol selector of a point’s symbology,you’ll see the 3D styles available by noting those prefixed with 3D polygon fill styles“3D”. Some of these styles contain common 3D character marker You can use 3D styles for polygons that allow you to depict theirsymbols with convenient sizes and colors. Other 3D styles fills as a variety of textures, including, for example, those that arecontain simple geometric shapes such as spheres, cubes, and vegetative or man-made.tetrahedrons. Yet other 3D styles contain models such asbuildings, street furniture, trees, and vehicles with real-worldsizing information.Use 3D point styles to render simple geometric shapes such asspheres or cubes. Or use them to make building models based on3D SYMBOLOGY 261
  • 266. You can use these 3D textures to model the grass in a park or thepavement of a parking lot. You might also use a style texture tosymbolize a surface, portraying the ground as a set of groundcovers.3D styles are the quick way to symbolize common 3D features.Use them as a shortcut to create realistic models or abstract 3Dworlds. Next, you’ll see how you can import and create your own3D symbols.262 USING ARCGIS 3D ANALYST
  • 267. Making 3D symbolsYou can make your own 3D symbols by composing them fromexisting symbols or by importing them as 3D models from otherformats. In this section you’ll learn how to do both.Constructing your own 3D symbolsYou can create your own 3D symbols to symbolize a particularfeature or add to a style’s contents. You might create a compositesymbol by combining unique symbols into one. See ‘Creatingnew symbols and map elements’ in the ‘Working with styles andsymbols’ chapter in Using ArcGIS ArcMap.Importing 3D models as symbolsYou can import OpenFlight (.flt), 3ds max* (.3ds), or VRMLmodels as 3D symbols. Use this feature if you have existing 3Dmodels that you’d like to use in 3D Analyst. You can import thesemodels when symbolizing a feature, or you can import them intoan existing or newly created style.OpenFlight models can be created using MultiGen–ParadigmModelBuilder 3D*. You can use ModelBuilder 3D to quicklygenerate 3D models of real-world buildings, objects, andvegetation for incorporation into an interactive display of 3D GIS.To create .3ds models, you can work in Discreet 3ds max, or use@Last Software SketchUp* as a tool for creating 3D models,then export them to .3ds format.3D SYMBOLOGY 263
  • 268. The 3D Symbol Opening the 3D Symbol Property EditorProperty Editor 1 1. In the TOC or the symbologyWhen using 3D symbols in the Layer Properties page, clickSymbol Property Editor, some the symbol whose propertiesfeatures specific to 3D become you want to change.available that are common to all 2. Click Properties.3D symbols, such as a 3Dpreview, 3D placement, and 3D The Symbol Property Editorthreshold. In this section, you’ll appears.learn how to accomplish tasksusing these features. 2264 USING ARCGIS 3D ANALYST
  • 269. Altering the Setting the origin of a 3D 1 symbolplacement of a 1. In the Symbol Property Editor,3D symbol click the 3D Placement tab.You can alter the placement of a 2. Slide the normalized origin3D symbol in relation to the offset slider for the axis youfeature it’s symbolizing. You want to modify to the positioncan set the origin of a 3D you want the origin to besymbol, then offset this within the symbol.normalized origin. In addition, 3. Click can alter the rotation of asymbol in the three axes that The origin is moved to thedefine 3D space. new position in the 3D Preview window.When you set the origin of a 3Dsymbol, you’re indicating whereon that symbol you want theorigin to be. For example, thedefault location of the origin fora sphere is at its center. You can 2 3set, or normalize, the origin tobe at its edge.3D SYMBOLOGY 265
  • 270. Offsetting a 3D Setting an offset for a 1 normalized origin of a 3Dsymbol symbolAfter you are satisfied with the 1. In the Symbol Propertynormalized origin of a 3D Editor, click the 3D Place-symbol, you may wish to ment tab.indicate an offset for thesymbol. You’ll use real-world 2. Type an offset for the axisunits to set offsets of 3D that you want to modify.symbols. 3. Click OK.Tip The normalized origin of the symbol is adjusted in the 3DSpecifying an offset Preview window.without typingInstead of typing in a number forthe offset, you can use the Up andDown buttons on the right side ofthe Offset text boxes. 2 3266 USING ARCGIS 3D ANALYST
  • 271. Tip Setting the rotation of a 3D symbol 1Specifying a rotationwithout typing 1. In the Symbol Property Editor,Instead of typing in a number for click the 3D Placement tab.the rotation angle, you can use theUp and Down buttons on the right 2. Type an angle of rotation inside of the Rotation angles text degrees for the axis you wantboxes. to modify. 3. Click OK. The symbol is rotated along the axis in the 3D Preview window. 2 33D SYMBOLOGY 267
  • 272. Scaling the size Scaling the size of a set of 3D symbols in a layerof 3D symbols 1 1. Right-click a layer symbol-3D Analyst stores models in its ized with 3D symbols andstyles with real-world sizes and click Scale 3D Symbols.attempts to provide sizing 2. Move the slider to the left oroptions for other symbols that to the right to decrease orwill suit your needs. However, increase the symbol’s scaledyou may find that after you size, respectively.symbolize a feature, you’ll needto adjust its scale in your 3. Optionally, click Suggest todocument. The Scale 3D offer a scale based on theSymbols dialog box, accessed layer’s extent and thefrom a layer’s context menu, symbol’s size.allows you to do this using on- 4. Click OK.the-fly feedback. 2 3 4268 USING ARCGIS 3D ANALYST
  • 273. Changing the dimensionsTip 1Specifying a dimension of the symbol axeswithout typing 1. In the Symbol Property Editor,Instead of typing in a number for click the 3D Characterthe size along an axis, you can use Marker, 3D Marker, or 3Dthe Up and Down buttons on the Simple Marker tab.right side of the Width (X), Depth(Y), or Size (Z) text boxes. 2. Optionally, uncheck Keep aspect ratio to change the dimensions of individual axes. 3. Under Dimensions, type a value in the text box for the axis you want to modify. 4. Click OK. The dimensions of the symbol are modified in the 3D Preview window. 2 3 43D SYMBOLOGY 269
  • 274. Using 3D styles Symbolizing a feature with a symbol in a styleto assign 1. In the table of contents, right-symbology click the layer and click Properties.Styles contain symbols withpreset properties that you might 2. Click the Symbology tab.use often. 3D styles offer 3. Click the Symbol button.geometric primitives as well as 4. Click More Symbols and click 1model libraries. the style you want to use. 2Tip 5. Optionally, click the Category dropdown menu and click theA shortcut to the Symbol category of the style youSelector want to use. uYou can invoke the Symbol Selector,the dialog box that lists symbols instyles, by clicking the feature class 3symbol in the table of contents. 5 4270 USING ARCGIS 3D ANALYST
  • 275. 6. Click the symbol you want to use. 7. On the Symbol Selector dialog box, click OK. 8. Click OK on the Layer Properties dialog box. 6 7 83D SYMBOLOGY 271
  • 276. Symbolizing Symbolizing a point as a 3D character marker notpoints with 3D included in a style 1symbols 1. In the TOC, click the symbol of the point feature class youPoints can be symbolized as 3D want to modify.character markers, 3D markers,and 3D simple markers. You can 2. Click Properties.create 3D symbols that use 3. Click the Type dropdownfonts on your system, choose menu and click 3D Character3D markers from existing styles, Marker Symbol.or import them from OpenFlight,3D Studio Max*, or VRML. 3D 4. Click the font dropdownmarkers are analogous to 3D menu and click the font youmodels. Finally, you can want to use. 2symbolize points as 3D simple 5. Click the Character buttonmarkers, which are 3D primi- and click the symbol youtives, such as spheres and want to use.cubes. 6. Optionally, click the Color dropdown menu and click the color you want to use. 3 7. Click OK. 4 5 6 7272 USING ARCGIS 3D ANALYST
  • 277. Symbolizing a point as an imported 3D marker 1. In the TOC, click the symbol 1 of the point feature class you want to modify. 2. Click Properties on the Symbol Selector dialog box. 3. In the Type dropdown menu, choose 3D Marker Symbol. 4. Browse to the model you want to use and click Open. 5. Click OK. 2 3 4 53D SYMBOLOGY 273
  • 278. Tip Symbolizing a point as aChoosing a quality level 3D simple marker notUse a higher quality level if you included in a style 1don’t have many features tosymbolize and a lower quality level 1. In the TOC, click the symbolif you have many features. Higher of the point feature class youquality renders at the expense of want to modify.performance. 2. Click Properties on the Symbol Selector dialog box. 3. Click the Type dropdown menu, and click 3D Simple Marker Symbol. 4. Click the Style dropdown menu, and click the shape 2 you want to use. 5. Optionally, click the Color dropdown menu and click the color you want to use. 6. Optionally, adjust the Quality 3 slider for shapes with curved surfaces. 7. Click OK. 5 4 6 7274 USING ARCGIS 3D ANALYST
  • 279. Symbolizing lines Symbolizing a line as a 3D simple line notwith 3D symbols included in a style 1You can symbolize line features 1. In the TOC, click the symbolas 3D simple lines or 3D of the line feature class youtextured lines. Use 3D simple want to modify.lines to symbolize lines as 3Dgeometric shapes, such as 2. Click Properties on thetubes and walls. Use 3D Symbol Selector dialog box.textured lines to turn your line 3. Click the Type dropdownwork into realistic roads, menu and click 3D Simplefences, or walkways. Line Symbol. 4. Optionally, click the Color dropdown menu and click the color you want to use. 5. Click the Style dropdown 2 menu and click the shape you want to use. 6. Optionally, slide the Quality slider to your desired quality level. 3 7. Click OK. 4 5 6 73D SYMBOLOGY 275
  • 280. Symbolizing a line as a 3D texture line with an imported 3D texture 1 1. In the TOC, click the symbol of the line feature class you want to modify. 2. Click Properties on the Symbol Selector dialog box. 3. Click the Type dropdown menu and click 3D Texture Line Symbol. 4. Browse to the texture you want to use and click Open. u 2 3 4276 USING ARCGIS 3D ANALYST
  • 281. 5. Optionally, check Vertical orientation to flip the geom- etry and texture vertically. 6. Click OK. 5 63D SYMBOLOGY 277
  • 282. Symbolizing Symbolizing a polygon with an imported 3Dpolygon fills with texture fill symbol 13D symbols 1. In the TOC, click the symbolPolygon fills and TIN triangles of the polygon feature classcan be symbolized with 3D you want to modify.symbols using the 3D Texture 2. Click Properties on theFill Symbol option. Use this Symbol Selector dialog box.option to realistically displayland use features or other 3. In the Type dropdown menu,polygonal areas. choose 3D Texture Fill Symbol. 4. Browse to the texture you want to use and click Open. u 2 3 4278 USING ARCGIS 3D ANALYST
  • 283. 5. Optionally, type an angle you want to use to rotate the texture. 6. Optionally, type a number for a specific axis to scale the texture in that direction. 7. Click OK. 5 6 73D SYMBOLOGY 279
  • 284. Saving the Exporting the current document styles to a newcurrent styles styleYou can easily create a new 1. Click Tools, point to Styles,style containing all the ele- and click Export Scene (orments, symbols, and symbol Globe) used in yourdocument. 2. Navigate to where you wantCreate and modify 3D elements to save the new style. 1and symbols as you design By default, the browser is setyour document, then save to your Styles folder.everything into a style. 3. Type a style name.Exporting styles allows you to 4. Click 3D elements and symbols 2from many styles into a singlestyle.TipHow are symbols stored ina 3D document?The items you draw in 3D—symbols and elements—are copiedinto the document. Therefore, you 4don’t need the original referencedstyles to open and draw thedocument again. 3TipCan I create a style from adocument without anyreferenced styles?If you need to modify the symbols ina document and don’t have theoriginal styles, you can create anew style by exporting the existingdocument elements and symbols.280 USING ARCGIS 3D ANALYST
  • 285. Creating a new styleOrganizing 3D 1. Click Tools, point to Styles,style contents and click Style Manager.The Style Manager dialog box 2. Click Styles and click Createlets you organize styles and New.their contents. You can cut, 3. Navigate to the Styles folder.copy, paste, rename, and modifyany style contents. You can 4. Type the name for the new 1also create new styles and style you’re creating.symbols. 5. Click Save.You can create a new style andcopy your personal stylecontents as well as othersymbols from other existingstyles. Or you can import 3Dmodels into styles. 2You can easily distinguishwhich folders contain elementsand symbols, which can bemodified, and which are empty. 3 Read/Write Read only EmptyTip 5Finding the Styles foldersBy default, the ESRI Styles folder isin the BinStyles folder where 4ArcGIS is installed. Your personalstyle folder is in your user profilelocation, for example,C:Documents andSettings<user>ApplicationDataESRI|ArcMap.3D SYMBOLOGY 281
  • 286. Tip Copying and pastingDeleting style contents style contentsRight-click any map element orsymbol and click Delete from the 1. Click Tools, point to Styles,context menu. and click Style Manager.There is no undo for delete, so you 2. Click the style folder whosemay want to move the element to contents you want to view.another folder as a backup ratherthan delete it. 3. Right-click an element and 1 click Cut or Copy. 4. Click another style folder of the same type.Tip 5. Right-click in the symbolWhat’s a symbol’s contents window and clickcategory? Paste.When you save a symbol, you can You can only paste into stylespecify a name and a category for folders that are the same typeclass distinction. The category can as the folder from which thebe used to create thematic classifi- element was copied.cations. You can also createsubcategories of styles. Categories 6. Type a new name for thecan be viewed in the Style Manager element. 2 3dialog box. You can change the name later by using Rename on the context menu. 5 6 4282 USING ARCGIS 3D ANALYST
  • 287. Creating and Creating a new symbol in 3 the Style Managermodifying 3D 1. In the style tree, click thesymbols and symbol folder in which youelements want to create more symbols. 2. Right-click in the open space 2You can use the Style Manager in the Symbol contentsdialog box to create new window, point to New, andsymbols or to modify an click the type of symbol youexisting symbol. want to create.To set or modify properties of Use the Symbol Propertyan element or symbol in a style, Editor to create the symboldouble-click it in the contents you want and click OK.window of the Style Manager. 1 3. Name the new symbol.This opens a property dialogbox and allows you to definethe appearance of the elementor symbol and save changeswithin the style.Since symbols and elements areorganized by type, you create anew symbol or element by firstidentifying the type, then byselecting the appropriate folder.Then, when you choose tocreate a new symbol or element,the properties you can choosefrom are only associated withthat symbol or element type. uTipUsing Microsoft ® Access toedit your stylesA style is a database. You can useAccess to edit names, check yourspelling, control sorting, andcomplete other tasks.3D SYMBOLOGY 283
  • 288. Layers appear in the listaccording to when they aredrawn. Therefore, the bottomlayer will be covered by thelayer listed above it.By adding or working withlayers, you can enhance thesymbols that already exist orcombine them to make newsymbols. The layers you usecan be a mixture of differentsymbol types and properties,such as color, width, and offset.Turning on or off a layer affectswhich layers will be viewed inthe preview. Locking andunlocking a layer does notaffect your capabilities in theSymbol Property Editor;however, it does affect theability to change the color inthe Symbol Selector you accessthrough the Layer Properties.There, if you change thesymbol color, only the unlockedlayers will change to the newcolor.TipUsing a shortcut to theSymbol Property Editordialog boxInstead of clicking the Propertiesbutton on the Symbol Selectordialog box, you can click thePreview window on the SymbolSelector dialog box.284 USING ARCGIS 3D ANALYST
  • 289. 3D graphics and textIN THIS CHAPTER 10 The information portrayed in your 3D documents isn’t always enough to make your point. In some cases you will want to add text and other graphics,• The 3D Graphics toolbar such as points, lines, and polygons, to bring attention to certain features or emphasize important areas. For example, you might define a study area by• 3D text enclosing it with a line or polygon boundary or label buildings with text• Changing properties of selected indicating their names. graphic elements You can use the 3D Graphics toolbar to help you accomplish these tasks.• Changing defaults for the way The 3D Graphics toolbar gives you the ability to digitize 3D text, points, lines, graphics appear and polygons based on elements in your display. The toolbar gives you the flexibility of dictating how these graphics are drawn by defining properties,• Graphics layers such as shape, color, font, location, and size. 285
  • 290. The 3D Graphics Turning on the 3D Graphics toolbartoolbar 1. Right-click in the gray areaThe 3D Graphics toolbar allows where toolbars appear andyou to make 3D point, line, click 3D Graphics. 1polygon, and text graphics.These graphics will draw based The 3D Graphics toolbar appears.on objects in the view. Usingthe toolbar, you can digitizepoints that might show areas ofinterest, lines that may encom-pass an area, polygons that fillan area, or text that mayannotate parts of your studyarea.See Also Digitizing a 3D pointSee ‘Changing defaults for the way graphicgraphics appear’ later in this 1. Click the New Marker button.chapter. 2. Click the point on the surface 1 or object you want to digitize. A point graphic is drawn at the location you digitized. You can set the default point to be any symbol you want. 2286 USING ARCGIS 3D ANALYST
  • 291. Tip Digitizing a 3D lineLine and surface graphicintersection 1. Click the New Line button.You can make a digitized lineconform to a surface by digitizing 2. Click the first point on the 1more vertices along its length, or surface or object you want tomake it intersect the surface by digitize.digitizing fewer vertices. Since the 3. Click any additional vertices,line digitizing tool is not a profilingtool (heights are obtained at double-clicking on the last 2 3 one.digitized points and not interpo-lated between), the resulting lines A line graphic is drawnmay not conform to the surface. To between the vertices youmake lines conform to the surface digitized.more closely, digitize more points.3D GRAPHICS AND TEXT 287
  • 292. Tip Digitizing polygonWhy doesn’t the digitized graphicspolygon conform to the 1. Click the New Polygonsurface?When you digitize a polygon button. 1graphic, only the vertices of the 2. Click the first point you wantedges you indicated by digitizing to digitize on the surfaceare interpolated from the surface object.or object. Therefore, in cases of 3. Click any additional vertices 2varying topography, polygon you want to create, double-interiors may not conform to clicking on the final point.surfaces. A special case where apolygon will conform is in a flat A polygon outline appears,area. If you find that polygon defined by the vertices youinterior nonconformance is a digitized.problem, you may want to set thedefault polygon fill to be No Color.If you need to show polygons withno color fill, see ‘Changing theproperties of selected graphicelements’ in the upcoming pages. 3288 USING ARCGIS 3D ANALYST
  • 293. Digitizing text3D text 1. Click the 3D Text tool.Use 3D text to label features and 2. Click the location on thelocations in your documents or surface or object where you 1make comments about unseen want the text to be placed.hazards and phenomena.Creating 3D text is as easy as 3. Type the text you want to display and press Enter.clicking on a location and typingthe text you want to appear. 3D text appears at theMany options are available for location you clicked.deciding how you want the textto look, including font, height, 2thickness, and color. 33D GRAPHICS AND TEXT 289
  • 294. Changing the color of aChanging selected graphicproperties of 1. Click the Select Graphicsselected graphic tool. 1elements 2. Click the graphic element you want to change.You can change the way thatexisting graphics appear. If a 3. Click the 3D Text Color 2 dropdown arrow for text, thegraphic element is selected, Fill Color dropdown arrow forthen any change you make polygon graphics, the Lineusing the properties buttons Color dropdown arrow forwill be honored. lines, or the Marker Color dropdown arrow for points.Tip 4. Click the color you want to use.Changing other drawingproperties The selected graphic isIf you select a graphic and click on changed to the color you 3the left side of the Color dropdown chose.arrow, you’ll invoke dialog boxesthat allow you to set additionalproperties. 4290 USING ARCGIS 3D ANALYST
  • 295. Changing Changing the default drawing properties of adefaults for the 3D point, line, or polygonway graphics graphic 1appear 1. Click Graphics and click Default Symbol Properties.If you want your graphics to bedrawn a certain way by default, 2. Click the Marker, Line, or Fill button to set default proper- 2you can do so by setting the ties for a point, line, ordefault properties for points, polygon symbol, respectively.lines, polygons, and text.Properties that you can set as 3. Click the symbol you want todefault include color, sizing, use.and font. You set the default 4. Optionally, click Color or Sizeproperties by choosing a to change the color or size ofsymbol that you would like to a drawn by default. If youwant the default symbol to 5. Optionally, click Properties toappear differently, you can access additional symbolchange its properties, in turn. properties.For example, when you chooseto change the default properties 6. Click OK. 4 7. Click OK.for a line symbol, you’ll invokethe Symbol Selector dialog box.At this point you can select anyline symbol from any available 5style as the default symbol. Ifyou want the default to be analtered version of one of thesesymbols, you’ll invoke theproperty pages for that symbol 3 6and change properties to suityour needs. 73D GRAPHICS AND TEXT 291
  • 296. Changing the default drawing properties of a 3D text graphic 1. Click Graphics and click Default 3D Text Properties. 1 2. Click the 3D Text tab to set default properties, such as 2 font, color, or orientation. 3. Click the Size and Position tab to change default sizing options. 4. Click OK. 3 4292 USING ARCGIS 3D ANALYST
  • 297. Graphics layers Creating a new graphicsDocuments can contain layers layer 1that are made up of graphics. 1. Click Graphics and click NewGraphics in a document can be Graphics Layer.stored in one layer, such as the A new graphics layer isdefault graphics layer, or in created in the TOC.multiple layers. If you begin tocreate graphics withoutdesignating a new graphicslayer as a target, the graphicswill be stored in the defaultgraphics layer. Optionally, youcan set 3D graphics to bestored in a graphics layer thatyou can create, name, and saveas a layer file.TipNaming graphics layersName a graphics layer listed in theTOC just like any other layer. Setting the target layer ofSelect the layer in the TOC, click it new graphicsagain, and type the name you’d liketo call the layer. 1. Click Graphics, point to Active Graphics Layer Target, 2 and click the graphics layer you want to set as the target for newly created graphics. All new graphics you create will now be added to the target graphics layer.3D GRAPHICS AND TEXT 293
  • 298. ArcGlobe Section 2
  • 299. Introducing ArcGlobeIN THIS CHAPTER 11 ArcGIS 3D Analyst enables effective visualization and analysis of surface data. Using 3D Analyst, you can view a surface from multiple viewpoints,• What can you do with ArcGlobe? query a surface, determine what is visible from a chosen location on a surface, and create a realistic perspective image by draping raster and vector data over a surface. The core of the 3D Analyst extension is the ArcScene and ArcGlobe applications. This section describes and demonstrates how ArcGlobe provides the interface for viewing multiple layers of GIS data and creating and analyzing surfaces. With 3D Analyst and ArcGlobe, you can • Use several forms of geographic data including vector data (buildings, parcels, roads, power lines, water hydrants, and soils) and raster data (digital elevation models [DEM], satellite imagery, digital orthophoto quadrangles [DOQ], and aerial photography). • Manage and navigate through extremely large databases (terabytes). • Extrude two-dimensional representations to three dimensions. • Create three-dimensional fly-through animations. • Perform analyses such as overlay, viewshed, and buffer. • Use GIS tools and functions in a 3D environment. • Apply various data layer effects such as transparency, lighting, shading, and depth priority. • View multiple perspectives simultaneously. 297
  • 300. What can you do with ArcGlobe?Visualizing complex data, and more display; you don’t have to wait for details to be paged into the display before you continue your navigation.ArcGlobe lets you work with your GIS data in 3D perspectivewhether its extent is local or worldwide and whether its size islarge or small. The interactive seamless display mechanism inArcGlobe allows a smooth visual transition between datasets.Individual datasets are merged into one of three unique globallayers categorized as floating, draped, or elevation. The drapedand elevation layers are the result of their constituent pieces ofdata; additional data increases the resolution of each global layer.You can effortlessly zoom from a view of the whole earth to yourlocal site using simple navigation tools. ArcGlobe controls thecaching and tiling of levels of detail of your data using distanced-based (scaled) dependencies, allowing you to load large datasetsinto a globe and easily navigate and interact with them. Themultitasked input and output processes in ArcGlobe allow you tonavigate while the details of your data are loaded into the The powerful display pipeline in ArcGlobe uses temporary files generated as you need them to improve the speed of display. This mechanism allows you to work with vast amounts of data as if they were small and simple. Application- and layer-level options allow you to choose caching mechanisms that work best for you. The flexibility of the caching options provide the opportunity for you to customize the way ArcGlobe deals with large volumes of data. To enhance your visualization experience, you can use multiple viewers to view data in different parts of the globe simultaneously, allowing you to gain perspective from different298 USING ARCGIS ARCGLOBE
  • 301. view points. You can also use specialized toolbars, such as the ArcGlobe Data media kit that contains a comprehensive set of3D Effects and Animation toolbars, to help you customize your imagery and elevation data. You can start working with ArcGlobevisualization experience. by using the navigation tools or by using a geographic index service, the ArcWeb Place Finder, to find locations by simplyUse your existing GIS data typing the name of the place you want to find.As long as your data has a spatial reference, you can add it toArcGlobe. ArcGlobe uses the world geodetic system 1984 (WGS-84) geographic datum to display data on a sphere. If your datauses a datum other than this, it will be transformed into the WGS-84 format for display.You can load virtually any type of data into ArcGlobe that youwould in any other ArcGIS application. Most types of raster andvector data that are spatially referenced can be loaded into aglobe. The spatial reference indicates where the data will appearon the globe.ArcGlobe is loaded with global and select local scale data rightout-of-the-box giving you a base from which to build your ownglobes. For example, you might enhance the base ArcGlobeelevation and imagery data with your own local elevation, image,and vector data, allowing you to zoom from a view of the entireearth down to your detailed local site. Explore areas of small extent Because ArcGlobe is able to view a globe at its full extent and at aUtilize large volumes of data detailed, magnified view, you can view your data even if it’s aArcGlobe can display substantial amounts of data quickly and small area. You have the whole globe as a reference to your data’seffectively. The data can be widespread or limited in extent with location, and when you zoom in, you have the globe surface as ahighly detailed or coarse resolution. background to your data.Start working with ArcGlobe immediately Explore areas of large extentArcGlobe ships with data already loaded. When you start the Since ArcGlobe can load worldwide data into one GlobeArcGlobe application, you’ll see a base globe that contains a Document, you can utilize data that covers the whole world,worldwide image and a countries feature class. In addition, zooming into the detail as you desire.supplemental data is provided in the ArcGIS 3D Analyst andINTRODUCING ARCGIS ARCGLOBE 299
  • 302. Explore discreet areas spread worldwideArcGlobe presents your data as three global layer categories thatare resolved to a higher degree at geographic locations whereyou’ve added more detailed data. In this way, your globe has ahigh degree of resolution at the areas in which you’re interested.You can examine your study area in one location and thennavigate to another location where you’ve added data.Make animationsArcGlobe includes a complete set of animation tools, enablingyou to create flybys, animated objects, time series progressions,and more. You can export these animations as QuickTime movies(.mov) or Audio Video Interleave movies (.AVI) that you can sharewith others including those who don’t have an ArcGIS system.Make 3D maps or real-world modelsArcGlobe incorporates 3D symbology that lets you displayabstract 3D geometric primitives as well as realistic typical orspecific models. This means that you can display standardcartographic symbols in 3D and real-world 3D models that youconstruct or choose to use from the rich 3D Style Librariesincluded with ArcGlobe. The wide variety of 3D symbols give youa high degree of flexibility in customizing your globes.Getting startedIn the next chapter you’ll learn how to display and navigate yourdata and perform analytic operations. You’ll find ArcGlobe to be apowerful and significant means of using your GIS data, while atthe same time, a simple and easy to use ArcGIS application.300 USING ARCGIS ARCGLOBE
  • 303. Using ArcGlobeIN THIS CHAPTER 12 ArcGlobe gives you a new and unique way to view and analyze your GIS data. Spatially referenced data is placed on a 3D globe surface, displayed in• Data you can use with ArcGlobe its true geodetic location. You can manipulate the globe and investigate and analyze its data while viewing the globe as a whole or by region. You can view• Default layers data covering a global extent and seamlessly zoom in to highly detailed,• Creating a new globe localized data. ArcGlobe allows efficient display and query of raster data, and it is integrated to function with the ArcGIS geodatabase while providing• The ArcGlobe document support for analysis in the geoprocessing environment.• Table of contents and layers ArcGlobe includes a comprehensive set of imagery and additional data is available on DVD, including elevation data for the entire earth. To help you• Navigating get started and to provide a backdrop for layers you’ll add, ArcGlobe starts• Globe layer properties with a set of default layers. Then, depending on how you want to use ArcGlobe, the default layers can be changed, replaced, or completely• Layer cache properties removed.• Globe properties Take some time to work through the ArcGlobe tutorials in Chapter 2, then consult this chapter for answers to questions you may have.• Application-level options Much of the functionality that is common to ArcGlobe and ArcScene is• Caching concepts discussed in Section 1 of this book.• And more 301
  • 304. Types of data you can use with ArcGlobeElevation dataYou use elevation data to give your globe relief. You can useelevation data as a source of base heights to drape other data.Different sets of elevation data are used in conjunction with oneanother. Multiple elevation models of varying extent andresolution are automatically seamed together as one logicalsurface. The more detailed data you add, the more detailed thefinal surface becomes. Elevations can be calculated from anyspatially referenced raster supported by ArcGIS. Feature data Feature data with a spatial reference can be added to ArcGlobe. You can add 3D features or make features render in 3D by setting elevation and extrusion properties. You can then perform analysis on the features, such as selection, or find a particular feature in a feature class.Globe surface without terrain (left) and with terrain from elevation data(right)Image dataYou can add spatially referenced images to ArcGlobe. The spatialreference will dictate where on the globe the data appears. If theimages have shared extent, the image with the higher degree ofresolution will take priority when displayed. Examples of data youmight use include satellite imagery, scanned maps, andcategorical data, such as land cover. The images added toArcGlobe are automatically draped on any elevation data with thesame extent if the image is added as a draped layer.302 USING ARCGIS 3D ANALYST
  • 305. Default layers Setting ArcGlobe to open without any defaultYou’ll notice that when you layersstart ArcGlobe, there areexisting layers in the table of 1. Click Tools and click Options.contents. These are the default 2. Click Default Layers.layers that are included with 3. Check Don’t use any defaultArcGlobe and are meant to be a layers. 1background or starting point atwhich you can begin using 4. Click OK.ArcGlobe. You can use thedefault layers provided, provide 2your own, or choose not tohave any default layers. 3 4USING ARCGLOBE 303
  • 306. User-defined Setting ArcGlobe to open with default layers youdefault layers provideYou can define the default 1. Click Tools and click Options.layers that are in the table of 2. Click Default Layers.contents when you start 3. Check Use my choice ofArcGlobe. These are known asuser-defined default layers. You default layers. 1indicate which layers you’d like 4. Optionally, click Make Defaultset as default by clicking a Layers From Current Docu-button that takes a snapshot of ment. 2what’s in the table of contents This captures the layers inat that time. Your choice of the table of contents as youruser-defined default layers will default remembered by the system,so you can toggle between the 5. Click OK.other choices and return to the 3option of loading your layersby default without having to 4specify them again. 5304 USING ARCGIS 3D ANALYST
  • 307. System default Setting ArcGlobe to open with the default layerslayers originally providedWhen you start ArcGlobe, 1. Click Tools and click Op-you’ll see a set of default layers the table of contents. These 2. Click Default Layers.are the system-supplied defaultlayers. You can always choose 3. Check Use the default layers 1to use them again after you’ve that come with ArcGlobe.set other choices. 4. Click OK. 2TipTwo sets of default layersOnce you create user-defineddefault layers, you’ll have two setsof default layers you can togglebetween: system and user-defined. 3You can always reset user-defineddefault layers to meet your currentneeds. 4USING ARCGLOBE 305
  • 308. Creating a new Adding data in ArcGlobeglobe 1. Click the Add Data button on the ArcGlobe standard toolbar. 1When you start ArcGlobe,you’ll see image data of the 2. Navigate to the folder thatearth drawn on a globe. A globe contains the data you want tois the sphere in the display add.window, or globe view, thatholds your data. You’ll prob- 3. Click the layer you want to 2ably want to add more data to add.the globe. You can add data as 4. Click Add.surfaces, images, or floatinglayers. Once you add data to a By default, ArcGlobe adds 3 data as draped layers, exceptglobe, you can change the way for features with z-values,the data is rendered by modify- which are added as floatinging a layer’s properties. You can layers.also change properties thataffect the whole globe, includ-ing background color options, 4globe illumination, and thevertical exaggeration of theglobe. See ‘The ArcGlobe tableof contents and layer types’ tolearn how to add data tospecific layer types.306 USING ARCGIS 3D ANALYST
  • 309. Adding data from ArcMap or ArcScene 1. Right-click the layer in the 1 ArcMap or ArcScene table of contents and click Copy. 2. Click the ArcGlobe window to make it active, right-click Globe layers, then click Paste Layer(s). 2USING ARCGLOBE 307
  • 310. The ArcGlobe Saving an ArcGlobe documentdocument 1 1. Click the Save button.The Globe document lets you 2. Navigate to the locationsave all the work you put into a where you’d like to save anglobe. A Globe document saves ArcGlobe document. 2information about paths to yourdata and the settings you have 3. Type a name for yourindicated in the globe’s and layers so the 4. Click time you open a savedGlobe document, it will appearjust as it did when you saved it.ArcGlobe documents have a.3dd extension. 4 3308 USING ARCGIS 3D ANALYST
  • 311. The ArcGlobe Adding elevation datatable of contents 1. Right-click Globe layers, point to Add Data, and clickand layer types Add elevation data. 1The table of contents in 2. Navigate to the folder thatArcGlobe differs slightly from contains the elevation rasterother ArcGIS applications in you want to add.that it has three ways ofdisplaying layers: the Display 3. Click the layer you want to add. 2and Source pages, which are 4. Click Add.the same as ArcMap andArcScene; and a third page that The raster is added as ancategorizes layers by their type: elevation source for theelevation, draped, or floating. global elevation layer.Elevation layers give terrain to 3a globe surface, draped layersare draped on the globesurface, and floating layers useoffsets to display above or 4below the globe surface.The globe surface is thesurface of the globe on whichdraped layers are drawn. Aglobe terrain is one or moreelevation layers representingone logical surface. Use rasterswith elevation data to definethe globe terrain, adding layersof higher resolution to theelevation layer category toincrease the detail of the globeterrain. Then drape rasterimages or feature classes onthe globe terrain by addinglayers to the draped layerscategory. Finally, add featureclasses or rasters to thefloating layer category and useUSING ARCGLOBE 309
  • 312. offsets or independent surfaces Adding draped datato create layers that floatindependent of the globe 1. Right-click Globe layers,surface. point to Add Data, and click 1 Add draped data. 2. Navigate to the folder that contains the data you want to add. 3. Click the layer you want to add. 2 4. Click Add. The layer is added as a layer draped on the globe surface. 3 4310 USING ARCGIS 3D ANALYST
  • 313. Tip Adding floating layersWhy doesn’t the layer I 1. Right-click Globe layers, 1added float? point to Add Data, and clickAfter you add the layer, you’ll need Add floating define more properties toindicate how you want it to float. 2. Navigate to the folder that contains the data you want to add.Tip 3. Click the layer you want to add.Can I float an elevationlayer? 4. Click Add.No. When you define an elevation The layer is added as a layer 2layer, it always becomes part of the that floats independent of theglobal surface. If you want to float globe surface.a layer on a surface independent ofthe globe surface, add that layer asa floating layer and use the 3elevation settings to browse to thesurface you want to use. 4USING ARCGLOBE 311
  • 314. Moving a layer to changeLayer drawing its drawing order on theorder globe surfaceThe order of draped layers Only layers that are draped 1listed in the Type page of the on the globe can have theirtable of contents determines drawing order the layers are drawn on the 1. In the Type page of the tableglobe. Within the draped of contents, click the drapedcategory, the layers listed at the layer whose drawing ordertop will draw over those listed you want to change.below them, and so on downthe list. ArcGlobe looks at 2. Drag the layer to the position 3properties of a layer, such as in the table of contents whereraster resolution, to make an you want it to be drawn.initial assumption about A black line appears todrawing priorities of layers. You indicate where the layer willcan also move draped layers in be dropped.the Type page of the table ofcontents to adjust their drawing 3. Release the mouse pointer toorder on the globe. drop the layer in its new position.312 USING ARCGIS 3D ANALYST
  • 315. Navigating in Navigating in global modeArcGlobe 1. Click the Navigate button on 1You view a globe in a globe the 3D View toolbar.viewer. The 3D View tools allow The Navigate tool is in spaceyou to navigate your data in mode by default; this is3D. Some of these tools are indicated by the Space Modesimilar to those in ArcMap and icon .ArcScene. Other tools arespecialized for the different The Navigate tool allows younavigation modes used in to rotate the globe and zoomArcGlobe. The Navigate and in and out.Fly tools have two modes in 2. Click the globe and drag toArcGlobe: global and surface. the right. 2Global mode allows you tonavigate without the sense of When you click the globe andgravitational influence; surface drag to the right, you rotatemode gives you a sense of up the data counterclockwiseand down as dictated by around the north–south axis.gravity. In both modes, clicking 3. Right-click the globe andthe left and right buttons and drag down.dragging up, down, left, or right When you right-click thelets you rotate the view, zoom globe and drag down, youin, and zoom out. zoom in to the globe. 3USING ARCGLOBE 313
  • 316. Tip Navigating in surfaceShortcut for centering a modetarget Surface mode is best used 1You can set the target when in when navigating near the globenavigation mode by pressing Ctrl surface.and clicking the mouse pointer atthe location you want to be 1. Click the Center on Targetcentered. button on the 3D View toolbar. 3 2. Click the location on the 2 globe surface where you want to set your target and center the view. The point you clicked is centered in the view. 3. Click the Navigate button on the 3D View toolbar. The Navigate tool is now in 4 surface mode, as indicated by the Surface Mode icon. In this mode, the Navigate tool allows you to rotate around the surface target, zoom in and out, and pan. The surface is always toward the bottom of the viewer to simulate the effect of gravity. 4. Click the globe and drag to the right. When you click the globe and drag to the right, you rotate the data counterclockwise around a vertical axis through the target.314 USING ARCGIS 3D ANALYST
  • 317. Tip Switching betweenKeyboard shortcuts for surface and global modeswitching the navigationmode 1. Click the Navigation Mode 1 button.To switch from global to surfacemode, press Ctrl and click the If you click it again, the modemouse pointer (you’ll center on the will toggle where you clicked). To When the Navigation Modeswitch from surface to global button is clicked on, themode, press Ctrl + Alt and click the navigation is set to globalmouse pointer. mode; otherwise, the navigation is set to surface mode.USING ARCGLOBE 315
  • 318. Using the camera Centeringtarget to simplify 1. Click the Center on Targetnavigation tool. 1 2 2. Click the location you want toYou can manipulate the camera occupy the center of thetarget to ease navigation to globe view.areas you want to explore. For The point you clicked isexample, when you zoom in to moved to the center of theyour data, you always zoom to view.your target. Changing thelocation of the target defineswhere you zoom in to your data.For more information about thevirtual camera, see ‘The camera,the observer, and the target’ inChapter 4 ‘Managing 3DData’of this book.316 USING ARCGIS 3D ANALYST
  • 319. Tip Zooming to a targetZoom to target shortcut 1. Click the Zoom to Target tool.You can zoom to a target when innavigation mode by pressing Ctrl 2. Click the location on the 1 globe where you want toand right-clicking the mouse. zoom. 2 The point you click becomes the center of your view as you zoom toward it.USING ARCGLOBE 317
  • 320. Zooming to a Zooming to a layerlayer’s extent 1. Right-click the layer to which you want to zoom and clickA useful way of examining a Zoom To area is to zoom to a The display zooms to thelayer’s extent in the display. extent of the layer.This method is a quick and easyway of zooming in to the area ofconcern, particularly if you 1have many study areas in theglobe.TipGraceful transitionsYou can set an option to animatecamera movements when zoomingin and out of the globe. Setting thisoption will animate the camera in asmooth fashion along the way toyour destination. To set this option,go to the Application page of theOptions dialog box and checkAnimate viewer when using toolsand commands. See ‘ArcGlobeapplication-level options’ in thischapter.TipZooming to more than onelayer’s extentYou can zoom to the extent of morethan one layer at a time by selectingmultiple layers in the table ofcontents and right-clicking to zoomto their combined extent.318 USING ARCGIS 3D ANALYST
  • 321. Using the Walk Using the Walk tool to navigatetool 1. Click the Walk button. 1Sometimes the best way to The cursor changes tonavigate your data is to fly indicate walk mode is active.above it or to walk through it atsurface level. Use the Fly tool 2. Click once in the center ofto gain unique perspectives the view.from the air. See ‘Navigating The tool enters the sus-through a scene using the Fly pended state. You can movetool’ in Chapter 7 ‘3D Visualiza- the mouse pointer to look intion’ of this book for more all directions, but there is noinformation about how to use forward or backward move-the Fly tool. Use the Walk tool explore your data from theground. Similar to the Fly tool, 3. Press arrow up or down onthe Walk tool allows you to the keyboard to increase ornavigate in walk mode, walking decrease the elevation,in any direction and moving respectively.forward or backward at different 4. Click the mouse to movespeeds. forward. Right-click to move in reverse. Successive clicks in either direction increase 2Tip the speed.Fine-tuning the walk speed Speed is indicated in theIn between mouse clicks, press thekeyboard arrow left or right to status window.increase or decrease speed, 5. Click the opposite mouserespectively. button to slow down incre- mentally and stop. Press Esc to immediately stop movement in either direction.USING ARCGLOBE 319
  • 322. Globe layer Opening a layer’s properties dialog boxproperties 1. Right-click the layer in theTo display data, ArcGlobe uses table of contents and clicksome properties that aren’t Properties.available in other ArcGIS The Layer Properties dialogapplications. These properties box is presented. The Layerbecome available when you add Properties dialog boxa layer to ArcGlobe and allow provides access to a layer’syou to set various options to 2D and 3D properties.determine how a layer getsdisplayed, how it gets elevation 1information, and how it’scached.TipAnother way to bring up theLayer Properties dialogboxDouble-click the layer’s name in thetable of contents.320 USING ARCGIS 3D ANALYST
  • 323. Setting the Setting the visible distance range of a layervisibility range of 1. Right-click the layer in thea layer table of contents whose visible distance range youSometimes you’ll only want a want to set and click Proper-layer to appear in the display ties.when you’re zoomed to aparticular distance. Using 2. Click the Globe General tab.visible distance ranges, you can 3. Check Don’t show layerset at what point a layer when zoomed. 1becomes visible in the display.Use visible distance ranges to 4. Type the distance in the outmake layers appear in the beyond text box at which youdisplay at defined distances want the layer to becomefrom the globe. For example, set invisible when you zoom out.the distance ranges for local 5. Type the distance in the in 2layers with small extents so beyond text box at which youthey’re visible only when you want the layer to becomezoom in to their proximity. invisible when you zoom in.Visible distance range units are 6. Optionally, click Checkthose defined as globe display visibility based on each tileunits in the General page of the distance to enable distanceGlobe Properties dialog box. visibility for discrete parts of the layer. 3Tip 7. Click OK. 4Setting a layer’s visibility The layer will be visible 5range from the context between the two You can also set the visibility 6You can also set a layer’s visibility range from the context menu,range by using the current using the current distances ofdistances in the display. In a the display. See the tip on thislayer’s context menu, use the Set page.Maximum Distance and SetMinimum Distance commands inthe Visible Distance Range context 7menu to capture distances used inthe display.USING ARCGLOBE 321
  • 324. Reclassifying a Redefining data as an elevation layerlayer 1. Right-click the layer you wantYou can change how a layer is to reclassify in the table ofcategorized in ArcGlobe—as an contents, point to Redefine 1elevation, draped, or floating layer, and click Redefinelayer—by using context menu layer as elevation.commands. After you categorize Note: This option is onlya layer, you’ll be able to use available for single banddifferent options that become rasters.available for a layer in thatcategory.Elevation layers provide asource of base heights for theglobe surface. Add rasters withheight source information aselevation layers to make a globeterrain.TipAdding a layer as anelevation sourceIf you know you want to add asingle band raster as an elevationsource, you can add it directly tothe Elevation layers category byright-clicking Globe layers,pointing to Add Data, and clickingAdd elevation data.322 USING ARCGIS 3D ANALYST
  • 325. Draped layers Redefining data as a draped layerDraped layers are layers thatuse the base heights of the 1. Right-click the layer you want to reclassify in the table ofglobe surface as elevation contents, point to Redefine 1sources. Drape a layer to showit on the globe surface. For layer, and click Redefineexample, you might drape an layer as draped.aerial photo and its associated The layer is draped on thefeatures on a mountain top. globe surface.Rasters and 2D features areadded as draped layers bydefault.TipAdding a layer as a drapedlayerIf you know you want to add adraped layer on the globe surface,you can add it directly into thedraped layers category by right-clicking Globe layers, pointing toAdd Data, and clicking Add drapeddata.USING ARCGLOBE 323
  • 326. What is a floating Defining a layer as a floating layerlayer? 1. Right-click the layer you wantA floating layer floats indepen- to redefine, point to Redefine 1dently of the globe surface. You layer, and click Redefinecan use offsets or independent layer as floating.surfaces to define where in 3Dspace the layer is drawn, aboveor below the globe surface. Usefloating layers to show utilities,aircraft, or clouds.TipAdding a layer as a floatinglayerIf you know you want to add alayer as a floating layer indepen-dent of the globe surface, you canadd it directly into the floatinglayers category by right-clickingGlobe layers, pointing to Add Data,and clicking Add floating data.TipHow can a surface not bepart of the globe elevation?An example of a surface that isindependent of the globe surface isan analytical surface, such as araster showing ozone concentra-tions. When you define an elevationlayer, it always becomes part of theglobe surface. If you want to float alayer on a surface independent ofthe globe surface, add or redefinethe layer as a floating layer and usethe elevation settings to browse tothe surface you want to use as asource of base heights.324 USING ARCGIS 3D ANALYST
  • 327. Tip Redefining a layer’sRedefining a layer using category in the table ofthe context menu contents 3You can also redefine a layer’scategory by right-clicking the layer 1. Click the layer in the table of 1in the table of contents and clicking contents whose category youRedefine layer. want to change. 2. Drag the layer to the new category. A black line appears where the layer will be dropped. 3. Release the mouse pointer to drop the layer in its new category. The layer is reclassified as the type you indicated. You may have to set some properties for the layer to display it properly.USING ARCGLOBE 325
  • 328. Layer cache Setting the cache removal option to deleteproperties a layer’s cache when diskYou can set options that control space is neededhow individual layer caches aretreated by ArcGlobe. These 1. Right-click the layer in theoptions dictate what happens to table of contents whosea layer’s cache when disk space cache properties you want tois needed in the globe cache or change and click Properties.after you exit ArcGlobe. 2. Check the check box under Cache removal options forSetting cache removal optionslets you manage the size of the Storage space is needed. 1ArcGlobe cache. When ArcGlobe needs toTo save a cached layer in the manage the size of the globeArcGlobe cache, you’ll have to cache, it may delete thissave the layer or save the Globe layer’s cache.document that contains thelayer.If you need to restrict the size ofthe globe cache, you canspecify that a layer’s cache willbe deleted either when storagespace is needed or when youexit ArcGlobe. 2326 USING ARCGIS 3D ANALYST
  • 329. Setting the cache removal option to remove a layer’s cache when removing the layer from the table of contents or when exiting ArcGlobe 1. Right-click the layer in the table of contents whose cache properties you want to change and click Properties. 2. Check the check box under 1 Cache removal options for Exiting the application or removing the layer. When the layer is removed from the table of contents or you exit ArcGlobe, the layer’s cache will be cleared. 2USING ARCGLOBE 327
  • 330. Globe display Changing the texturing mode of an image layerlayer properties 1. Right-click the image in theGlobe display properties dictate table of contents and clickhow a layer will appear in the Properties.globe view. Use globe display 2. Click Globe to determine araster’s or rasterized feature’s 3. Click the Image Texturingtexturing mode or drawing mode dropdown arrow andpriority, whether a feature is select the texturing mode yourasterized, or how 3D symbols want to a feature class are scaled. 4. Click OK. 1A raster’s texturing modedetermines how it will look inthe display. In general, imageswill look better with a smooth 2texture mode. Use the NearestNeighbor texture mode forlayers that should preservedistinct boundaries, such as arasterized polygon feature classwith distinct polygonal bound-aries. 3 4328 USING ARCGIS 3D ANALYST
  • 331. Rasterizing Setting a layer to draw as 1 vectorsfeatures 1. In the table of contents, double-click the layer.Rasterizing features inArcGlobe allows you to 2. Click Globe Display. 2maintain any cartographic 3. Uncheck Rasterize featuresymbology that you may have layer.saved in ArcMap. It’s also aneffective way to drape features 4. Click OK.on the globe surface. By The features will be drawn asdefault, 2D points, lines, and vectors.polygons are added toArcGlobe as rasterizedfeatures. 3D points and linesare added as vectors. 3TipRasterized polygonsLines and points can be displayedas vectors or rasterized. Polygonsare always rasterized.Tip 4Why are some, but not all,features rasterized bydefault?By default, polygons, 2D lines, and2D points are rasterized. 3D linesand 3D points are not rasterized bydefault.USING ARCGLOBE 329
  • 332. Feature Setting the feature 1 properties of features in aproperties layerTo display features, a scale 1. In the table of contents, 2needs to be set. ArcGlobe double-click the layer whosemakes an estimate about what feature properties you wantthe scale should be, but you to set.may need to alter the scale forthe layer on the Feature 2. Click Globe dialog box. 3. Click the Feature PropertiesWhen you set a scale for a button.layer, you indicate at what 4. Move the Scale slider todistance, or scale, the features select an appropriate scalein that layer become visible. range to display the features in the layer. Use the images, level, approximate scale, and 3 distance information to help you decide which scale is appropriate for the layer. 5. Click OK. 6. On the Layer Properties 6 dialog box, click OK. 4 5330 USING ARCGIS 3D ANALYST
  • 333. Scaling 3D Scaling the size of 3D 1 symbols in a layersymbols 1. Double-click the 3D SymbolsWhen you symbolize points in layer in the table of contents.ArcGlobe using 3D symbols, 2. Click Globe may want to scale thesymbols so they maintain their 3. Check the Scale 3D symbols 2size in relation to the globe and with distance check box.the rest of its layers when you 4. Click OK.zoom in and out. You can turnon the option to scale 3Dsymbols in the Globe Displaypage of the Layer Propertiesdialog box.Tip 3What kinds of layers canbe scaled?Only point feature layers contain-ing 3D symbology can be scaled. 4USING ARCGLOBE 331
  • 334. See-through Setting the see-through value for a floating layerposition 1. In the table of contents, right-Floating layers can be given a click the layer whose see-drawing order based on their through value you want to setposition relative to the globe and click Properties.surface when using 2. Click Globe Display.transparencies. For example, if 3. Click the See-throughyou have a subterranean layer position dropdown arrow andbelow the globe surface and an select a value.aerial layer above the globe 4. Click OK. 1surface, and you’d like to settransparencies for the layers soyou can see them all, you canuse see-through positions for thefloating layers. Picture the globe 2surface with a value of zero. Thesubterranean layer would receivea value of -1, and the aerial layerwould receive a value of +1. If 3you then added a subterraneanlayer with a lower elevation, itwould receive a see-throughvalue of -2, and an aerial layerwith a higher elevation wouldreceive a value of +2. 4332 USING ARCGIS 3D ANALYST
  • 335. Globe properties Changing the vertical exaggeration of the globeGlobe properties, including surfacevertical exaggeration, back- 1. In the table of contents, right- 1ground characteristics, andillumination, can be changed to click Globe layers and clicksuit your particular needs. This Globe Properties.can be done to enhance realism 2. Click General.or accentuate specific aspects 3. In the Vertical Exaggeration 2of your globe. Changes made inthe Globe Properties dialog box Of globe surface dropdownapply to the current document. combo box, choose a value.Use vertical exaggeration to Alternately, you can type aemphasize the topography of value.the globe surface or floating 4. Click OK.layers. The surface of the globe is exaggerated by the value 3 you indicated. 4USING ARCGLOBE 333
  • 336. Changing the vertical exaggeration of the floating layers 1. In the table of contents, right- 1 click Globe layers and click Globe Properties. 2. Click General. 3. In the Vertical Exaggeration 2 Of floating layers dropdown combo box, choose a value. Alternately, you can type a value. 4. Click OK. Floating layers are exagger- ated by the value you indicated. 3 4334 USING ARCGIS 3D ANALYST
  • 337. Background Selecting and setting 1 bimodal backgroundoptions color optionsYou can choose from a variety 1. In the table of contents,of options to customize thebackground of your globe. By double-click Globe layers. 2default, the background color 2. Click Background.changes depending on the 3. Click the Mode dropdowncamera observer location. You arrow and click Transitionalcan change whether the color. 3background is a single color orthe default transition between 4. Click the Space color dropdown arrow, and select a 4two colors and how the space color.transitional colors changebased on camera observer 5. Optionally, type an upper and 5elevation. lower limit for the transition zone.When using transitional color 6mode, the space color is the The colors will begin to fadebackground of the globe view into each other based on thewhen viewing the globe from thresholds you define here.high altitudes. The sky color is 6. Click the Sky color dropdownthe background when you’re arrow, and select a sky color.viewing closer to the globesurface. 7. Click OK. 7USING ARCGLOBE 335
  • 338. Selecting single color backgrounds 1. Right-click Globe layers and click Globe Properties. 1 2. Click Background. 3. Click the Mode dropdown arrow and click Single color. 4. Click the Sky color dropdown 2 arrow, and select a color for the background. 5. Click OK. 3 4 5336 USING ARCGIS 3D ANALYST
  • 339. Illumination Turning on illumination based on the sun’soptions positionYou can choose to illuminate 1. Right-click Globe layers and 1the globe based on the sun’s click Globe Properties.position or not illuminate it at 2. Click Sun Position.all. You can define where thesun’s rays strike the globesurface most directly geo- 3. Check Enable sun lighting. 2 4. Click OK.graphically or based on time. Inaddition, you can modify the The globe is illuminated based on the position of theway the unlit side of the globeis illuminated. sun on the dialog box. 3 4USING ARCGLOBE 337
  • 340. Changing the illumination based on geography 1. In the table of contents, right- 1 click Globe layers and click Globe Properties. 2. Click Sun Position. 3. Check Enable sun lighting. 2 4. Click and drag the yellow sun symbol to the place on the map that you want the 3 sun to shine on. 5. Alternately, type in the latitude and longitude values of the location you’d like the 4 sun to shine. 6. Optionally, move the slider to indicate how bright you want 5 the unlit side of the globe to be. 7. Click OK. 6 7338 USING ARCGIS 3D ANALYST
  • 341. Changing the illumination based on time 1. In the table of contents, right- 1 click Globe layers and click Globe Properties. 2. Click Sun Position. 3. Check Enable sun lighting. 2 4. Click Set sun position based on time, and type in values of the time you want the sun 3 position to be. Optionally, click Now for real- time sun lighting. 5. Optionally, move the slider to indicate how bright you want the unlit side of the globe to be. 6. Click OK. 4 4 5 6USING ARCGLOBE 339
  • 342. ArcGlobe Animating camera movements whenapplication-level transitioning betweenoptions viewsYou can set options that control 1. Click Tools and click Options.the way ArcGlobe behaves 2. Click General.every time it starts. These 3. Check the Animate viewer 1options stay the same unless when using tools andyou change them. Application- commands check box.level options include settingsthat affect the way ArcGlobe Optionally, move the Speedbehaves, how the slider to indicate how quickly 2geoprocessing framework the transitions will occur.behaves, table behavior, and 4. Click rasters are handled. Next,you’ll see how to change someoptions that control the wayArcGlobe behaves.You can control the way thecamera behaves when it movesbetween locations. You can set 3options that move the camera 3smoothly between the locationsyou zoom to. 4340 USING ARCGIS 3D ANALYST
  • 343. Setting the Setting the default view for full extentdefault view at 1. Right-click Globe layers andfull extent click Globe Properties. 1You can set the location you 2. Click General.see on the globe when you 3. In the Full View Observerzoom to full extent. This way, Position window, click the 2when you zoom to the full location of the globe youextent of the globe, you’ll see want to see when you clickthe part of the world you’re Full Extent.interested in. A red X appears at the location you clicked, indicat- ing the part of the globe that will be shown as default in the full extent position. Optionally, type in decimal degree values in the Latitude and Longitude text boxes. 3 4. Click OK. 3 4USING ARCGLOBE 341
  • 344. Application-level Changing how much memory ArcGlobe usescache options 1. Click Tools and click Options.You can control the way 2. Click Cache.ArcGlobe manages caches,including the size of the memory 3. In the Size of memory cache text box, type the amount ofcache, the location or size of thedisk cache, or the default tile size memory you want ArcGlobe 1 to use.of feature caches. 4. Click OK.The size of the memory cache If you indicate a value higherdetermines how much of yourcomputer’s physical memory than is available on your computer, ArcGlobe will 2ArcGlobe will use. The first time begin to use virtual start ArcGlobe, it willestimate how much memory touse based on how much is 3available on your computer. Youcan manually change theallocation. 4342 USING ARCGIS 3D ANALYST
  • 345. Disk caches Setting the globe cache locationArcGlobe creates files on yourcomputer’s disk that help it 1. Click Tools and click Options.efficiently navigate and display 2. Click These disk caches may be 3. Check Use a disk cache totemporary or permanent, as you improve visualization speed.choose. See ‘What is cachingand how do I use it?’ later in 4. In the Cache path text box, 1this chapter for more informa- type the path to the locationtion about layer caching and that you want your it gets stored on disk. Optionally, browse to theLayer caches are stored in the location. 2ArcGlobe disk cache. By 5. Optionally, in the Maximumdefault, the globe’s cache is size text box, type thecreated in your user profile maximum size that you wantlocation, for example, the globe cache to be onC:Documents andSettings<user>Local disk. 3SettingsTempGlobeCache. The maximum size of the 4You can change the location of globe cache applies only to 5the globe cache and determine temporary caches (thoseits maximum size. deleted on exit). A globe cache that contains perma- nent layer caches may exceed the indicated maxi- mum cache size. 6. Click OK. 6USING ARCGLOBE 343
  • 346. Level of detail Changing the level of detail displayed by imageYou can control how much of an and elevation rastersimage or elevation raster’squality, or level of detail, is used 1. Click Tools and click Options.when displaying it in ArcGlobe. 2. Click Level of Detail.When changing the level of 3. Move the Image slider to thedetail setting for rasters, be desired level of detail. 1aware that the higher the level of 4. Move the Elevation slider todetail, the more compromised the the desired level of detail.performance. 5. Optionally, click Restore Defaults to return to the 2 original settings. 6. Click OK. 3 4 5 6344 USING ARCGIS 3D ANALYST
  • 347. Compression Turning off radiometric compressionoptions 1. Click Tools and clickArcGlobe uses compression Options.techniques to more efficiently 2. Click Compression.display rasters. These optionsare on by default to increase the 3. Uncheck Use radiometricperformance of images in compression of colors to 1ArcGlobe, but you can choose 16 turn off the different com- 4. Click OK.pression types. Note that ArcGlobe usesRadiometric compressionreduces the number of bits used radiometric compression by default to more effi- 2to display the colors of an ciently display images.image. Using compression Turning off this featuresacrifices some image quality at may result in poor perfor-the benefit of performance by mance.reducing the cache size. 3 4USING ARCGLOBE 345
  • 348. Lossy spatial Turning off lossy spatial compressioncompression 1. Click Tools and click Options.Lossy spatial compression 2. Click Compression.reduces cache storage space byspatially averaging the distribu- 3. Uncheck Use lossy spatialtion of colors in an image. This compression.results in increased perfor- 4. Click OK. 1mance. Note that ArcGlobe uses lossy spatial compression by default to more efficiently display images. Turning off 2 this feature may result in poor performance. 3 4346 USING ARCGIS 3D ANALYST
  • 349. Elevation Turning off elevation compressioncompression 1. Click Tools and click Options.Elevation compression reduces 2. Click Compression.the number of bits used todisplay the elevation range of a 3. Uncheck Compress elevationraster. This decreases the cache range to 16 bits (1 m. verticalsize and increases performance. accuracy). 1 4. Click OK. Note that ArcGlobe uses elevation compression by default to more efficiently display elevation rasters. 2 Turning off this feature may result in poor performance. 3 4USING ARCGLOBE 347
  • 350. Table of contents Setting table of contents display preferencesoptions 1. Click Tools and click Options.The ArcGlobe table of contents 2. Click Table Of Contents.has three different pages: theDisplay, the Type, and the 3 Optionally, check the boxesSource pages. The Display next to the layers you want topage shows a simple list and see in the table of contents. 1legend of the layers in your Uncheck them if you don’tdocument. The Type page want to see them.shows the layers in yourdocument categorized by their Optionally, set the displaylayer classification. The Source order of the pages. 2page shows the paths to the 4. Click a layer to select it.layers in your document. 5. Click the Up or Down arrowUsing application-level options, buttons to change the orderyou can choose the ordering of in which the pages arethese pages, indicating which’d like to see by default. 6. Click OK. 3 4 5 The setting you choose willSee Also be the default every time you start ArcGlobe.See ‘The ArcGlobe table of contentsand layer types’ section earlier inthis chapter for more informationabout the table of contents andlayer classification. 6348 USING ARCGIS 3D ANALYST
  • 351. What is caching Saving a layer’s cacheand how do I 1. In the table of contents, right- click the layer whose cacheuse it? you want to save and click Save As Layer File.When you add a layer toArcGlobe, it creates a tempo- 2. Navigate to the locationrary file, or cache, that helps where you want to save theyou display and navigate your efficiently. A cache stores 3. Type the name you want tothe data and information that save the layer as. 1allow ArcGlobe to better 4. Click Save.manage your environment bycontrolling levels of detail. The layer’s cache is pre-Caches may be on-demand, or served through reference bypartial, containing some the layer file. Saving thedetails of the layer, or full, cache preserves optimizationcontaining all the details the of areas you’ve visited. 2layer has to offer. As younavigate your layers inArcGlobe, the parts of the datayou zoom to are cached on-demand to disk. Revisitingthese areas subsequent timeswill be faster because they arealready cached. In addition,it’s possible to generate apartial or full cache as a batchprocess. This is beneficial if 4you need ArcGlobe to displayany potential area at a speci-fied level of detail (partialcache) as fast as possible or 3any potential area at thehighest level of detail as fastas possible—for example,when giving demonstrationsto an audience.Most of the time, it’s better tocache part of your data, uUSING ARCGLOBE 349
  • 352. building an on-demand disk Generating a cachecache as you navigate andsaving disk space. By doing 1. In the table of contents, right- click the layer you want tothis, the places you visit (andmay visit again) will become cache and click Generate 1part of the cache, but places Data never visit don’t become 2. Drag the From LOD slider topart of the cache. A conse- the minimum scale at whichquence of an on-demand cache you want to cache the a slightly increased time to 3. Drag the To LOD slider to thebuild the cache and bring the maximum scale at which youhighest detail into the viewwhen visiting new places. An want to cache the layer.alternative to the on-demand Setting the levels of detail atcache is to build a cache at a which you want to create aspecified level of detail. This cache makes a partial cacheprocess makes a cache of the of the data. The remainingentire layer at the specifiedlevel of detail. For people who levels will be cached on- demand. 2want the highest resolution of To create a full cache, set the 3the data available in the From LOD slider to theshortest amount of navigation smallest scale, or Near, andtime for any potential region of set the To LOD slider to thethe data, creating a full cache of largest scale, or Far.the data may be the bestalternative. The possibility of 4. Click OK.long processing times and The caching process begins.increased disk space require- Depending on the size of thements make full caching a data, the process may takesecondary option to on-demand some time to complete. 4caching. Consider your needsby evaluating whether you will Click Cancel to terminate theonly need quick access to the caching process.highest detailed data in a Don’t forget to save the datarelatively smaller number of as a layer file or to save theareas, whether you can work document to preserve thewith all areas at a specified level cache.of detail, or whether you needquick access to all areas at theirhighest level of detail.350 USING ARCGIS 3D ANALYST
  • 353. A variety of cache manage-ment options are available,allowing you to delete cacheson layer removal or exit, deletecaches as space is needed,and set the size and location ofthe ArcGlobe cache folder.TipAnother way to save acacheWhen you save a globe document,the state of caches for layers in thetable of contents is saved.USING ARCGLOBE 351
  • 354. 12 3D featureGlossary A representation of a three-dimensional, real-world object in a map or scene, with elevation values (z-values) stored within the feature’s geometry. Besides geometry, the feature may have attributes stored in a feature table. 3D graphic A representation of a three-dimensional, real-world object in a map or scene, with elevation values (z-values) stored within the feature’s geometry. Unlike 3D features, the graphic does not have attributes. 3D model A paradigm used to portray an object in three dimensions. 3D shape A point, line, or polygon which stores z-coordinates, or elevation, in addition to x,y coordinates as part of its geometry. A point has one z-coordinate; lines and polygons have one z-coordinate for each vertex in the shape. 3D style In ArcScene and ArcGlobe, a library containing 3D symbols. 3D symbol A symbol that has properties which allow it to be rendered in three dimensions. altitude 1. The height, z-value, or vertical elevation of a point above or below a given reference datum (such as sea level) or surface (such as land). 2. The height above the horizon, measured in degrees, from which a light source illuminates a surface; used when calculating a hillshade or for controlling the position of the light source in a scene for on-the-fly shading. animation In ArcScene and ArcGlobe, a collection of tracks in a document that defines dynamic property changes related to associated objects. 353
  • 355. Animation Manager autocorrelationIn 3D Analyst, the interface in which the properties of keyframes Generically, a statistical measure which describes the extent toand tracks can be edited, and an animation can be timed and which one property changes as another changes. In GIS it is usedpreviewed. to refer to a statistical measure which describes the extent to which the value of an attribute at geographically referencedarea points changes as a function of the distance and orientation1. A fundamental spatial unit consisting of a closed, two- between them. dimensional shape defined by its boundary. Its extent is usually defined in terms of an external polygon or by a azimuth contiguous set of grid cells. A compass direction. In 3D Analyst and Spatial Analyst, the2. A mathematical calculation of the size of a two-dimensional direction from which a light source illuminates a surface is called geographic feature, measured in square units. the azimuth.aspect backgroundThe compass direction in which a topographic slope faces, In ArcScene or ArcGlobe, the backdrop of the view. The color ofusually expressed in terms of degrees from the north. Aspect can the background can be set to suggest sky, empty space, or anybe generated from continuous elevation surfaces. The aspect color that improves visualization.recorded for a TIN face is the steepest downslope direction of theface. The aspect of a cell in a raster is the steepest downslope base heightdirection of a plane defined by the cell and its eight surrounding The height at which a surface, raster, or feature is drawn in aneighbors. scene. Base height for features and rasters can be set from a surface such as a digital elevation model (DEM) or using aattribute constant value or expression. Features with z-values stored in1. Information about a geographic feature in a GIS, generally their geometry can have their base height set using the z-values. stored in a table and linked to the feature by a unique identifier. Setting the base heights from a surface is also called draping. For example, attributes of a river might include its name, length, and average depth. bin 1. In a variogram map, each cell that groups lags with similar2. In raster datasets, information associated with each unique distance and direction. Bins are commonly formed by dividing value of raster cells. the sample area into a grid of cells or sectors, and are used to3. Cartographic information that specifies how features are calculate the empirical semivariogram for kriging. displayed and labeled on a map; the cartographic attributes of 2. In a histogram, user-defined size classes for a variable. a river might include line thickness, line length, color, and font.354 USING ARCGIS 3D ANALYST
  • 356. camera draped layerIn 3D Analyst, an object that defines the perspective of a scene’s A layer in ArcGlobe that has been categorized to be draped ondisplay. top of the globe surface.Catalog tree drapingIn ArcCatalog, a hierarchical view of folder connections that Setting the base height for features or a surface using a surface.provide access to GIS data stored on local disks or shared on a For example, an aerial photograph might be draped over a digitalnetwork, and allows users to manage connections to databases elevation model (DEM) to create a realistic terrain visualization.and GIS servers. drawing prioritycategorical raster The order in which layers that occupy the same x,y,z positions areA raster that represents the world with a set of values that have drawn in a scene. For example, if a road feature layer and anbeen aggregated into classes. For example, a satellite image that orthophoto are draped over the same terrain model, the roads andhas been reclassified to extract a number of landcover types is a raster may appear patchy or broken up where they coincide. Thecategorical raster. Categorical rasters represent an area, but the drawing priority for the raster can be reduced so it will appearvalues do not form a continuous surface. below the features. The drawing priority can only be changed for polygon features and surfaces.continuous rasterA raster that represents the world with a set of values that vary edgecontinuously to form a surface. For example, a raster digital A line between two nodes, points, or junctions that forms theelevation model and an interpolated chemical concentration boundary of one or more faces of a spatial entity. In an image,surface are continuous rasters. edges separate areas of different tones or colors. In topology, an edge defines lines or polygon boundaries; multiple features incontour line one or more feature classes may share edges. In a TIN, the lineA line drawn on a map that connects points of equal elevation connecting nodes.above a datum, usually a mean sea level. elevation layercull A layer in ArcGlobe that has been categorized to help define theIn ArcScene and ArcGlobe, to selectively choose not to draw one geometry of the globe surface.side of an areal feature. extrusiondisk cache Projecting features in a two-dimensional data layer into three-In ArcGlobe, the folder on a computer’s disk drive where dimensional space: points become vertical lines, lines becomeArcGlobe stores layer cache files. walls, and polygons become solid blocks. Uses of extrusion include showing the depth of well point features or the height of building footprint polygons.GLOSSARY 355
  • 357. face globeA region bounded by a closed sequence of edges. Faces are In ArcGlobe, the sphere in a globe view on which data iscontiguous and do not overlap. On a TIN surface, each face is depicted.defined by three edges and three nodes, and is adjacent to one ofthree faces of the surface. TIN faces store aspect and slope globe documentinformation, and may have tag values. A disk-based representation of the globe view or views contained in ArcGlobe. Globe documents have a .3dd extension.floating layerA layer in ArcGlobe that has been categorized to float globe propertiesindependently above or below the globe surface. In ArcGlobe, properties that can be set for a globe document. These include vertical exaggeration, background color, or sunfull cache position.In ArcGlobe, a layer cache saved on disk that contains completelevels of details for the entire layer. globe terrain A globe surface with base heights supplied from an elevationgeospecific model layer.A model that is based on a real-world feature. For example, ageospecific model for the White House would look exactly like globe viewthe White House and be used to represent the White House on a In ArcGlobe, the display window in which a globe can be of Washington, D.C.See also geotypical model. hillshading 1. Shadows drawn on a map to simulate the effect of the sun’sgeotypical model rays over the land.A symbolic representation for a class of objects, such as 2. On a raster, a simulated shadow effect achieved by assigninggovernment buildings. For example, on a map of the United an illumination value from 0 to 255 to each cell according to aStates, a white building with a dome on top could be used as a specified azimuth and altitude for the sun. Hillshading createsgeotypical model for all state capitols. a three-dimensional effect.See also geospecific. IDWglobal mode See inverse distance weighted (IDW).A navigation mode in ArcGlobe during which the camera target isalways at the center of the globe. image A raster-based representation or description of a scene, typically produced by an optical or electronic device such as a camera or a scanning radiometer. Common examples include remotely sensed356 USING ARCGIS 3D ANALYST
  • 358. data (for example, satellite data), scanned data, and photographs. lagAn image is stored as a raster dataset of binary or integer values The line (vector) that separates any two locations. A lag hasthat represent the intensity of reflected light, heat, sound, or any distance (length) and direction (orientationother range of values on the electromagnetic spectrum. An imagemay contain one or more bands. line of sightinterpolation 1. A line drawn between two points, an origin and a target, in a three-dimensional scene that shows whether the target