Edit sketches An edit sketch lets you perform various editing tasks, such as adding new features, modifying features, and reshaping features. Tasks are listed in the Current Task dropdown list on the Editor toolbar. You can use the tasks in the Current Task dropdown list in conjunction with a sketch you create to edit your geographic data in ArcMap. Here are some examples: The Create New Feature task uses a sketch you create to make the new feature. The Select Features Using a Line task uses a sketch you create to select features; the features the line intersects are selected. The Cut Polygon Features task uses a line sketch you draw to cut a polygon.
Context menus for editing A context menu is a floating menu that pops up at the location of the pointer when you press the right mouse button. There are two types of context menus related to sketches, a sketch tool context menu and a sketch context menu. Sketch tool When using the Sketch tool, you can access the Sketch tool context menu by right-clicking the mouse away from the sketch you’re creating. The menu has options for placing the vertices and segments specifically where you want them. For example, you can set a segment to be a certain length or angle or create a vertex at a specific x,y coordinate location. Sketch The Sketch context menu works more directly with the sketch as a whole. With this menu, you can: Add vertices Move vertices Delete vertices Switch the direction of the sketch Reduce the length of the sketch Display the properties of the sketch shape
Modifying the length of a sketch At times you may want to modify the length of a sketch. This can be done with the Trim tool. If you digitize a sketch of 30 meters in length, then realize that the sketch should be 20 meters, simply right-click on the last added vertex, select Trim, and type 10 (the amount that should be trimmed), and press Enter on the keyboard. The sketch will retract to 20 meters.
Finishing a sketch There are two ways to finish a sketch: to finish it, or finish part of it. Finish Sketch Right-click where you have just finished digitizing, and from the context menu click Finish Sketch. Finish Part Right-click where you have just finished digitizing, and on the context menu click Finish part. The Finish part option is useful for creating multipart features, e.g.many islands that belong to one country.
Lengths There are two ways you can specify length using the sketch tool context menu. Specify a length constraint from the last vertex You can choose Length from the context menu when your next vertex will be at a certain distance from the current vertex. This will create a line segment of a specific length. Change the length of the last segment The Change Length option will allow you to change the length of the last segment created. While changing the length of the last segment, ArcMap honors the direction of this last segment and will maintain it’s angle.
Edit tasks In ArcMap, you have many different edit tasks available. These different tasks work in conjuncture will the selected sketch tool. A sample of these edit tools are discussed in the next few pages.
Extend/Trim Features task Many a times when creating new features, you may end up with features that are either too short or too long. There are tools in ArcMap to remedy these undershoots or overshoots. Extend feature to the sketch You can fix an undershoot with the Extend/Trim features task. First you need to select the feature to be extended. Then sketch a short line to where you want to extend it (most likely another line). Once you sketch the second vertex, the selected feature extends to meet your sketch. Trim features on the right side of the sketch You can also fix an overshoot with the Extend/Trim features task. First you need to select the feature to be trimmed. Then sketch a short line to where you want to trim it to (most likely another line). Once you digitize the second vertex, the selected feature trims where it meets your sketch. The sketch will disappear from the screen.
Modify Feature task At times you may want to modify the shape of an existing feature. The Modify Feature task will allow you to edit the vertices of an existing feature. While using the Modify Feature task, you may only modify one feature at a time. Hover your mouse pointer over the vertex you want to modify. You will notice that your pointer changes shape. Click on the vertex and drag it to a new location.
Reshape and Cut Feature tasks The Reshape Feature task can be used to digitize a sketch that will become part of the feature you are reshaping. You start with sketching the new shape of the feature making sure your sketch intersects with the existing feature. The Cut Polygon Features task can be used to sketch a line that will split one polygon into two. This is a tool specifically useful for parcel management. The sketched line must intersect both sides of the polygon feature to cut it.
Working with shared features Two features, in the same feature class or between two feature classes may share a common boundary. Suppose the boundary changes and you wanted to make sure that the changes are made in both feature classes. The Shared Edit tool can be used for this purpose. When you edit the boundary selected with the Shared Edit tool, all coincident vertices and boundaries and any connected vertices or boundaries are modified.
Auto Complete Polygon The Auto Complete Polygon task will allow you to add a polygon to the edge of existing ones without having to sketch in a duplicate boundary between them. Using this task you will sketch in all the polygon boundaries except the one shared by the other adjacent polygon(s).
Feature creation tools From the Editor menu, there are a variety of tools for creating new features. Tools that create features in the target layer may use features selected in other layers to create new features. For example, create a new water main parallel to a road feature. Tools like Split and Merge will create new features from features in the same layer.
Copy Parallel The Copy Parallel tool allows you to create a new feature parallel, on either side, to an existing one. You will be able to specify the distance between the original line and the new parallel one. A positive distance between the parallel lines will create the new parallel line to the right side of the feature; negative values to the left. It would help to change the symbol from a simple line to one with an arrow in order to see this relative location, i.e. to see the “right side” of the feature. The new parallel line is created as a new feature in the target layer. You can use the Copy Parallel command, for example, to create a street centerline or a gas line that runs parallel to a road.
Union and Intersect The Union command combines features from different layers into one feature while maintaining the original features and attributes. For example, you can create a sales territory from several ZIP Codes. You can also create a multipart feature using the Union command by combining nonadjacent features from different layers. For example, to create a sedimentary rock polygon in a new rock classification layer given selected clay and quartz polygons in an existing rock composite layer, you would use the Union command to combine the clay and quartz features to create a new multipart sedimentary rock feature in the rock classification layer. Although the features may be from different layers, the layers must be of the same type—either line or polygon. The new feature is created in the current layer without attribute values. The Intersect command creates a new feature from the area where features overlap. For instance, you can create a new sales territory out of overlapping trade areas. You can find the intersection between features of different layers, but the layers must be of the same type (either line or polygon). The original features are maintained and the new feature is created without attribute values in the current layer. You must manually enter attribute values for the new feature.
Split and Merge The Merge command combines features of the same layer into one feature. The features must be from either a line or a polygon layer. You can also merge nonadjacent features to create a multipart feature. For example, you could merge the individual islands that make up Hawaii to create a multipart polygon feature. When you merge features, the original features are removed and the new feature’s attributes are copied from the feature with the lowest ID number (the oldest feature). Use the Split command when you know the distance at which you want to split the line, measured from either the first or last vertex. You can also use this command when you want to split a line at a certain percentage of the original length. For example, you can use the Split command to split a power line at a known distance along the line when you want to add an electrical pole that requires its own service. The Split dialog box displays the length of the original feature in current map units to help you split it accurately. When you split the line using the Split command, the attributes of the original line are copied to each of the new lines.
ADD XY DATA TOOL Takes a table containing XY data & Creates a layer from it. The table must alreadty contain two separate fields containing X & Y ( these X & Y fields must be Numeric data type ) coordinate data. The new layer will contain one point for each record in the table.
Exercise : - Provided RO details along with the Coordinates. Plot these RO locations
Go to Tools & click Add XY data tool.
Add XY window appears
FILE HAVING THE COORDINATES SELECT THE FIELDS HAVING X & Y COORDINATE DEFINE PROJECTION OF THE COORDINATE AVAILABLE IN THE FILE
TOPOLOGY Topologies maintain high-quality spatial data by ensuring that your features conform to simple rules. When you set up a geodatabase with a topology, you specify which feature classes participate in the topology and define rules that control when and how features can share geometry. For example, in a geodatabase of states and coastlines, you might have a rule stating that polygons cannot overlap each other and another rule that the coastline must coincide with the boundaries of the states. These rules would help you ensure, when updating the state boundaries to match the coastline, that you don't inadvertently create places where the states overlap or where a state's coastal edge doesn't match the shape of the coastline.
For Using this option all the layers must be in Featureclasses & should be inside a dataset.
This option is not available in ARCVIEW license.
Right click on the dataset having the layers for which the topology is to be checked.
Go to New topology option.
TOPOLOGY – DEFINE RULES ENTER TOPOLOGY NAME & DEFINE THE TOLERENCE ( GENERALLY KEEP THE TOLERENCE AS THE DEFAULT VALUE ) SELECT THE LAYERS FOR WHICH THE TOPOLOGY IS TO BE CHECKED ASSIGN RANKS TO THE LAYERS ( FOR OUR PURPOSE DON’T CHANGE THE RANK, KEEP THE DEFAULT VALUES ) CLICK ON THE ADD RULE BUTTON TO ADD THE TOPOLOGICAL RULES ONCE THE ADD RULE BUTTON IS CLICKED THE WINDOW SHOWN ABOVE APPEARS & THE USER CAN DEFINE THEIR RULES ON THE LAYERS. ONCE RULES ARE DEFINED CLICK NEXT & FINISH BUTTON. THE USER WILL RECEIVE A MESSAGE AS SHOWN ABOVE. CLICK ON YES BUTTON
TOPOLOGY – VIEWING THE TOPOLOGICAL ERRORS ONCE THE PROCESS IS COMPLETE, A TOPOLOGY LAYER IS CREATED INSIDE THE DATASET. ADD THIS TOPOLOGY LAYER IN ARCMAP & THE TOPOLOGICAL ERRORS WILL BE DISPLAYED
Error Summery can also be generated -
Right Click on the Topology layer in Arccatalog
Go to Properties Errors Generate Summery
GEOMETRIC NETWORK A geometric network is a connectivity relationship between a collection of feature classes in a feature dataset. Each feature has a role in the geometric network of either an edge or a junction. Multiple feature classes may have the same role in a single geometric network.
Create in ArcCatalog
Edit in ArcMap
Analyze in ArcMap
Up and downstream tracing
Find connected features
Find the most efficient path
For Building Geometric Network the Layer must be featureclass inside a Dataset
This option is not available in ARCVIEW license.
Right click on the dataset having the layers for which GEOMETRIC Network is to be created.
Go to New Geometric Network option.
GEOMETRIC NETWORK - CREATION The window shown above appears. Select the first option which is by default. Click Next Select the featureclass & provide the Geometric Network Name. Click Next Keep the default option available here Keep the default option available here. This will not allow you to connect to a Road Edge without creating a node. Keep the default option available here. This will retain you network feature as it is. Select Yes if you want to define any weight or select No. If Yes is selected define the Weight Name & Type
GEOMETRIC NETWORK - CREATION Select the fields that will contain the values of the Weight Defined Summery of the options selected is displayed, Click on the Finish Button After creation of Geometric Network Junction Layer is formed & a Geometric Network icon is created.