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Working With Gm Transp Manager

  1. 1. ® Working with GeoMedia Transportation Manager
  2. 2. Working with GeoMedia Transportation Manager DJA084590 (6.0.3)
  3. 3. Warranties and Liabilities All warranties given by Intergraph Corporation about software are set forth in the End User License Agreement and Limited Product Warranty (“EULA”) provided with the software, and nothing stated in or implied by this document or its contents shall be considered or deemed a modification or amendment of such warranties. The information and the software discussed in this document are subject to change without notice and should not be considered commitments by Intergraph Corporation. Intergraph Corporation assumes no responsibility for any error that may appear in this document. No responsibility is assumed by Intergraph for the use or reliability of software on equipment that does not meet the specified requirements as found in the product Readme. Trademarks Intergraph and GeoMedia are registered trademarks of Intergraph Corporation. Windows and Windows XP are registered trademarks of Microsoft Corporation. MapInfo is a registered trademark of MapInfo Corporation. Dynamap/2000 is a registered trademark of Tele Atlas North America, Inc. FLEXlm is a registered trademark of Macrovision Corporation. Oracle is a registered trademark of Oracle Corporation. All other brands and product names are trademarks of their respective owners. Copyright © 2001-2006 Intergraph Corporation. All Rights Reserved. Including software, file formats, and audiovisual displays; may be used pursuant to applicable software license agreement. Contains confidential and proprietary information of Intergraph and/or third parties, which is protected by copyright and trade secret law, and international treaty, and may not be provided or otherwise made available to end users other than purchaser without proper authorization from Intergraph Corporation. The software discussed in this document is furnished under a license and may be used or copied only in accordance with the terms of the accompanying license. Because these documentation files are delivered as PDF files, an industry-standard format, most photocopy vendors can print them for you from the PDF file. You have permission to make two hardcopies per license for your internal, non-commercial use. Purchaser shall not have reproduced more than two hardcopies per license without prior written permission from Intergraph Corporation. Copyright for the Canadian National Transformation Version 2 Software: ©1995. Her Majesty the Queen in Right of Canada, represented by the Minister of Natural Resources. Produced under licence from Her Majesty the Queen in Right of Canada, represented by the Minister of Natural Resources. Software based on the National Transformation Version 2 developed by Geodetic Survey Division, Geomatics Canada. Copyright for Dynamap/2000 ©2002-2005 Tele Atlas North America, Inc. This product contains proprietary and confidential property of Tele Atlas North America, Inc. Unauthorized use, including copying for other than testing and standard backup procedures, of this product is expressly prohibited. Restricted Rights Legend Software is subject to the U.S. Export Regulations. Any diversion of the software that is contrary to U.S. law is prohibited. Use, duplication, or disclosure by the government is subject to restrictions as set forth below. For civilian agencies: This was developed at private expense and is “restricted computer software” submitted with restricted rights in accordance with subparagraphs (a) through (d) of the Commercial Computer Software - Restricted Rights clause at 52.227-19 of the Federal Acquisition Regulations (“FAR”) and its successors, and is unpublished and all rights are reserved under the copyright laws of the United States. For units of the Department of Defense (“DoD”): This is “commercial computer software” as defined at DFARS 252.227-7014 and the rights of the Government are as specified at DFARS 227.7202-3. Unpublished rights reserved under the copyright laws of the United States. Terms of Use Use of this software product is subject to the EULA delivered with this software product. Intergraph Corporation Huntsville, Alabama 35894-0001
  4. 4. What do you think about Working with GeoMedia Transportation Manager? DJA084590 We would like your opinion of this document. Please help us improve our documentation by completing this questionnaire. Write your comments or circle your responses to the questions. Circle all responses that apply, and include additional pages of comments if you wish. When you have completed the questionnaire, fold and mail it to Intergraph. Postage is prepaid. Thank you for taking the time to let us know what you think. 1. How much of this document have you worked through? 1. 1 - 2 - 3 - 4 - 5 (1=entire document, 2=most of it, 3=about half, 4=about one-third, 5=one-fourth or less) 2. How easy was this document to read and understand? 2. 1 - 2 - 3 - 4 - 5 (1=difficult . . . 5=easy) 3. How easy was it to find specific information in this document? 3. 1 - 2 - 3 - 4 - 5 (1=difficult . . . 5=easy) 4. What was your primary intent in using this document? 4. 1 - 2 - 3 - 4 - 5 (1=orientation . . . 5=thorough understanding) 5. How well did this document satisfy this intent? 5. 1 - 2 - 3 - 4 - 5 (1=poorly . . . 5=very well) 6. Have you used Intergraph software before? (1=yes, 2=no) 6. 1 - 2 7. What percentage of your work time is spent using Intergraph software? 7. 1 - 2 - 3 - 4 - 5 (1=10% or less, 2=25%, 3=50%, 4=75%, 5=90% or more) 8. How would you rate your level of software use? 8. 1 - 2 - 3 - 4 - 5 (1=demanding . . . 5=casual) 9. Did this document help you learn to use the software in a satisfactory way? 9. 1 - 2 (1=yes, 2=no) 10. How would you rate this document overall? (1=poor . . . 5=excellent) 10. 1 - 2 - 3 - 4 - 5 11. Have you used Intergraph documentation before? (1=yes, 2=no) 11. 1 - 2 12. Please describe and note page numbers of any errors or inconsistencies in this document. 13. How would you improve this document? Name Date Organization Phone Address City State Zip Code Thanks again for your time and effort.
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  6. 6. Table of Contents Start Here ................................................................................................................................... 1-1 What’s New in Transportation Manager 6.0.3....................................................................... 1-1 Overview of the Document .................................................................................................... 1-2 Documents Delivered............................................................................................................. 1-3 Document Conventions.......................................................................................................... 1-4 Introduction to Linear Referencing ......................................................................................... 2-1 What is Linear Referencing?.................................................................................................. 2-1 Linear Referencing and GeoSpatial Technology ................................................................... 2-2 LRS Linear Features and Event Data..................................................................................... 2-3 Multilevel Linear Referencing Systems (MLRS) .................................................................. 2-5 Linear Referencing Analysis................................................................................................ 2-14 Linear Referencing System Maintenance ............................................................................ 2-16 Introduction to Working with Multilevel LRSs...................................................................... 3-1 LRS Analysis Using a Multilevel LRS .................................................................................. 3-1 Maintaining a Multilevel LRS ............................................................................................... 3-8 Working with the LRS Metadata Definition Command........................................................ 4-1 The LRS Metadata Definition Command Workflow to Create New Metadata Definitions .. 4-4 The LRS Metadata Definition Command Workflow to Modify an Existing LRS Definition 4-9 Working with the Interactive LRS Calibration Command ................................................... 5-1 The Interactive LRS Calibration Command Workflow ......................................................... 5-2 Working with the LRS Calibration Command....................................................................... 6-1 The LRS Calibration Command Workflow ........................................................................... 6-2 Working with the LRS Validation Command ........................................................................ 7-1 The LRS Validation Command Workflow ............................................................................ 7-2 Working with the Reformat Linear Collections Command .................................................. 8-1 The Reformat Linear Collections Command Workflow........................................................ 8-2 Working with the Create Intersection Markers Command .................................................. 9-1 The Create Intersection Markers Command Workflow ......................................................... 9-4 Working with the Insert LRM Segment Command ............................................................. 10-1 The Insert LRM Segment Command Workflow.................................................................. 10-1 i
  7. 7. Working with GeoMedia Transportation Manager Working with the Split LRM Segment Command ................................................................ 11-1 The Split LRM Segment Command Workflow ................................................................... 11-2 Working with the Redigitize LRM Segment Command ...................................................... 12-1 The Redigitize LRM Segment Command Workflow .......................................................... 12-3 Working with the Merge LRM Segments Command........................................................... 13-1 The Merge LRM Segments Command Workflow............................................................... 13-2 Working with the Delete LRM Segment Command............................................................. 14-1 The Delete LRM Segment Command Workflow ................................................................ 14-1 Working with the Output Linear Datum Command ........................................................... 15-1 The Output Linear Datum Command Workflow ................................................................. 15-3 Working with the Interactive Multilevel LRS Conflation Command ................................ 16-1 The Interactive Multilevel LRS Conflation Command Workflow ...................................... 16-3 Working with the Multilevel LRS Conflation Command .................................................... 17-1 The Multilevel LRS Conflation Command Workflow ........................................................ 17-3 Working with the Multilevel LRS Validation Command .................................................... 18-1 Data Integrity Rules ............................................................................................................. 18-1 Geometry Rules.................................................................................................................... 18-2 LRM Rules........................................................................................................................... 18-4 Schema ................................................................................................................................. 18-6 The Multilevel LRS Validation Command Workflow......................................................... 18-7 Working with the Display LRM Command .......................................................................... 19-1 The Display LRM Dialog Box............................................................................................. 19-1 The Display LRM Command Workflow ............................................................................. 19-3 Working with the LRS Event Overlay Command................................................................ 20-1 The LRS Event Overlay Command Workflow .................................................................. 20-11 Working with the Resolve LRS Event Overlaps Command................................................ 21-1 The Resolve LRS Event Overlaps Command Workflow..................................................... 21-2 Working with the LRS Event Conversion Command.......................................................... 22-1 The LRS Event Conversion Command Workflow .............................................................. 22-1 Working with the Convert Intersection Referenced Events Command ............................. 23-1 The Convert Intersection Referenced Events Command Workflow.................................... 23-1 ii
  8. 8. Table of Contents Working with the LRS Event Generation Command .......................................................... 24-1 The LRS Event Generation Command Workflow ............................................................... 24-2 Working with the Create Intersections and Midblocks Command .................................... 25-1 The Create Intersections and Midblocks Command Workflow........................................... 25-3 Working with the Insert LRS Event Command ................................................................... 26-1 The Insert LRS Event Command Workflow........................................................................ 26-1 Working with the LRS Keys for Coordinate Events Command ......................................... 27-1 The LRS Keys for Coordinate Events Command Workflow............................................... 27-1 Working with the Routes and Sections to LRS Command .................................................. 28-1 The Routes and Sections to LRS Command Workflow....................................................... 28-1 Working with the LRS Event Transform Command........................................................... 29-1 The LRS Event Transform Command Workflow ................................................................ 29-1 Working with the LRS and Marker Properties Dialog Boxes............................................. 30-1 The LRS Properties Dialog Box Workflow for an LRS Feature Class................................ 30-1 The Marker Properties Dialog Box Workflow for a Marker Feature Class ......................... 30-2 Working with the Event Properties Dialog Box.................................................................... 31-1 The LRM-based Event Properties Dialog Box Workflow ................................................... 31-1 The Datum-based Event Properties Dialog Box Workflow................................................. 31-3 Working with the Coordinate System Dialog Box................................................................ 32-1 The Coordinate System Dialog Box Workflow ................................................................... 32-1 Working with the LRS Data Preparation Workflows.......................................................... 33-1 Reformat Linear Collections ................................................................................................ 33-1 Validate and Fix Geometry .................................................................................................. 33-2 Validate and Fix Connectivity ............................................................................................. 33-3 Calibrate the LRS................................................................................................................. 33-5 Validate the LRS .................................................................................................................. 33-5 Fix the LRS .......................................................................................................................... 33-6 Index the LRS ...................................................................................................................... 33-6 Working with Intersection Preparation Workflows............................................................. 34-1 Intersection Preparation for Single Level LRSs................................................................... 34-1 Intersection Preparation for Multilevel LRSs ...................................................................... 34-8 iii
  9. 9. Working with GeoMedia Transportation Manager Working with the Single Level to Multilevel LRS Conversion Workflow ......................... 35-1 Data Model Design .............................................................................................................. 35-1 Source Data Preparation....................................................................................................... 35-3 Data Conversion................................................................................................................... 35-4 Final Touches ....................................................................................................................... 35-4 Working with the LRS Annotation Workflows .................................................................... 36-1 Annotate Digitizing Direction.............................................................................................. 36-1 Annotate Begin and End Measurements .............................................................................. 36-3 Annotate Even Measures Along the LRS ............................................................................ 36-8 Working with the LRS Analysis Workflows ......................................................................... 37-1 Aggregate Point Event Data onto Linear Segments............................................................. 37-1 Aggregate Point Event Data onto Intersections ................................................................... 37-7 Aggregate Linear Event Data within Boundaries .............................................................. 37-12 Aggregate Segment Event Data onto Linear Segments by Proportion .............................. 37-18 Introduction to Routing .......................................................................................................... 38-1 What is a Routing Network? ................................................................................................ 38-1 Edge-Node Connectivity...................................................................................................... 38-2 Impedance ............................................................................................................................ 38-4 Turn Tables .......................................................................................................................... 38-4 Restrictors ............................................................................................................................ 38-6 Stops..................................................................................................................................... 38-8 Routing Analysis.................................................................................................................. 38-9 Routing Maintenance ......................................................................................................... 38-10 Working with the Build Network Command ........................................................................ 39-1 The Build Network Command Workflow............................................................................ 39-1 Working with the Stop Manager Command......................................................................... 40-1 The Stop Manager Workflows ............................................................................................. 40-1 Working with the Turn Editor Command ............................................................................ 41-1 The Turn Editor Workflow .................................................................................................. 41-1 Working with the Restrictor Editor Command.................................................................... 42-1 The Restrictor Editor Workflow .......................................................................................... 42-1 Working with the OneWay Editor Command ...................................................................... 43-1 The OneWay Editor Workflow ............................................................................................ 43-1 Working with the Blockage Editor Command...................................................................... 44-1 The Blockage Editor Workflow ........................................................................................... 44-1 iv
  10. 10. Table of Contents Working with the Display OneWays Command................................................................... 45-1 The Display OneWays Workflow........................................................................................ 45-1 Working with the Display Blockages Command .................................................................. 46-1 The Display Blockages Workflow ....................................................................................... 46-2 Working with the Easy Path Command................................................................................ 47-1 The Easy Path Workflow ..................................................................................................... 47-2 Working with the Best Path Command................................................................................. 48-1 The Best Path Workflow...................................................................................................... 48-2 Working with the Find Closest Stops Command.................................................................. 49-1 The Find Closest Stops Workflow ....................................................................................... 49-2 Working with the Network Coverage Command ................................................................. 50-1 The Network Coverage Command Workflow ..................................................................... 50-2 Working with the Generate Path Directions Command ...................................................... 51-1 The Generate Path Directions Command Workflow ........................................................... 51-1 Working with the Configure Network Dialog Box ............................................................... 52-1 The Configure Network Dialog Box Workflow .................................................................. 52-1 Working with the Stop Properties Control ........................................................................... 53-1 The Stop Properties Control Workflow ............................................................................... 53-1 Working with the Routing Data Maintenance Workflows .................................................. 54-1 The Dynamic Routing Data Maintenance Workflow .......................................................... 54-1 Manual Routing Data Maintenance – The Initial Network Creation Workflow.................. 54-2 Manual Routing Data Maintenance – The Network Update Workflow .............................. 54-3 The Routing Network Validation Workflow ..................................................................... 54-10 Working with the LRS-based Routing Restrictions Workflow........................................... 55-1 A. How to Reach Intergraph.................................................................................................... A-1 Electronic Self-Help Support ................................................................................................ A-1 B. GeoMedia Transportation LRS Data Structures...............................................................B-1 Overview................................................................................................................................B-1 Single Level LRS Data Structures .........................................................................................B-2 Additional Multilevel LRS Data Structures .........................................................................B-13 Event Data Structures...........................................................................................................B-14 v
  11. 11. Working with GeoMedia Transportation Manager Additional Multilevel LRS Event Structures .......................................................................B-19 Multilevel LRS Supporting Tables ......................................................................................B-21 GeoTrans Transportation Data Model….............................……………………………….B-24 C. Working With Oracle LRS and ArcView Data ................................................................ C-1 Working with Oracle LRS Data .............................................................................................C-1 Working with ArcView Data .................................................................................................C-1 Index .......................................................................................................................................... IN-1 vi
  12. 12. Start Here What’s New in Transportation Manager 6.0.3 The major new feature of GeoMedia Transportation Manager 6.0.3 is the option to create and use Multilevel LRSs. This is important functionality that addresses many common problems facing transportation agencies, including: • Handling multiple linear referencing methods – This allows Event data collected using a wide variety of route measurement and naming schemes to be used together when analyzing a transportation system. • Handling multiple network representations – This harmonizes the use of multiple network representations that perhaps originate from other transportation agencies at different levels of government. You can choose to analyze your Event data using any of the available network representations. • Securing Event data location stability – One of the dangers of a linear referencing system is that as the network changes (for example, road name changes, realignments, and recalibrations), the location of Event data can be incorrectly changed. Intergraph’s Multilevel LRS can prevent this from happening. • Preserving the history of the network – When used with GeoMedia Transaction Manager, Intergraph’s Multilevel LRS provides the ability to create, maintain, and analyze a temporal history of a linear referencing system and the Event data associated with it. This is a powerful tool for analyzing the effectiveness of maintenance and corrective actions executed by the agency. Of course GeoMedia Transportation Manager also has the tools to create and maintain a Multilevel LRS. Beyond the introduction of Multilevel LRS support, this release also provides important new functionality in the following areas: • LRS Conflation – Conflation, the selective copying of data from one source to another, is especially tricky for transportation networks due to the fact that no two representations of the same network are modeled or segmented in the same way. The conflation tools in this release overcome those obstacles. Furthermore, when used in conjunction with the tools in the GeoMedia Fusion product, GeoMedia Transportation Manager can perform conflation for an entire data set in a very automated manner. • LRS Definitions – With this release, the LRS Property settings can be stored centrally in your enterprise database where they can be set once and be available to all users. • Region IDs – We have introduced the concept of Region IDs, which allows you to subdivide your network into logical units. This often improves performance when the entire network is not needed for a particular analysis. 1-1
  13. 13. Working with GeoMedia Transportation Manager • Intersection-referenced Events – We now support Event data that is located by its distance and direction from intersections. This even includes the capability to resolve ambiguous locations associated with roads that cross more than once. • Aggregation – Often transportation agencies like to analyze their network at intersections and the “midblocks” between intersections. This release provides a tool to make these analyses easier, more accurate, and the end results more useful. • Routing improvements – This release has two improvements to our routing tools. One is the option to enforce turn restrictions at intermediate stops, which is important for applications such as large vehicle routing. Another improvement is the ability to edit the restrictors used by an existing path query via the Query Properties dialog box, which facilitates what if analyses. Overview of the Document This document contains information on using GeoMedia Transportation Manager for linear data analysis and routing analysis. The structure of this document is as follows: • There are two major divisions: Chapters 2-37 pertain to Linear Referencing Systems (LRS), and Chapters 38-55 pertain to Network Routing. • Chapter 2 provides an introduction to the basic concepts behind linear referencing, and Chapter 3 provides a good overview of how to work with Multilevel LRSs. • Chapters 4-18 provide step-by-step instructions on how to use each of the LRS (Linear Referencing System) Maintenance commands. • Chapters 19-29 provide step-by-step instructions on how to use each of the LRS Analysis commands. • Chapters 30-32 provide step-by-step instructions on how to use four of the elements common to many of the LRS commands included in this product: the LRS Properties dialog box, the Markers Properties dialog box, the Event Properties dialog box, and the Coordinate System dialog box. • Chapters 33-37 provide instruction on common workflows used in the preparation and analysis of linear data. • Chapter 38 provides an introduction to the basic concepts behind network routing. • Chapters 39-46 provide step-by-step instructions on how to use each of the Routing Maintenance commands. • Chapters 47-51 provide step-by-step instructions on how to use each of the Routing Analysis commands. • Chapters 52-53 provide step-by-step instructions on how to use two of the elements common to many of the Routing commands included in this product: the Configure Network dialog box and the Stop Properties control. 1-2
  14. 14. Start Here • Chapters 54-55 provide instruction on common workflows used in Routing maintenance and analyses. • Appendix B provides details of the LRS data structures supported by the GeoMedia Transportation product line. • Appendix C provides instruction for using Oracle LRS or ArcView data with the GeoMedia Transportation product line. Each section of this document takes you through a systematic process to use the software commands. Documents Delivered The following online documents are delivered with GeoMedia Transportation Manager: Document Number Description Working with DJA0845 An overview of the workflows and commands for GeoMedia Online only performing most software tasks. Available online in Transportation .pdf format at Start > All Programs > GeoMedia Manager Transportation Manager > User Documentation > Working with GeoMedia Transportation Manager. Installing DJA0853 Instructions for installing the product. Available online GeoMedia Online only in .pdf format at Start > All Programs > GeoMedia Transportation Transportation Manager > User Documentation > Manager Installing GeoMedia Transportation Manager. GeoMedia Online only Programmer's guide for objects, methods, and Transportation properties. Available from the Program Manager Object FilesGeoMediaHelp folder or at Start > All Programs > Reference GeoMedia Transportation Manager > Developer Documentation > GeoMedia Transportation Manager Object Reference. GeoMedia Online only Object diagrams for programmers. Available online in Transportation .pdf format at Start > All Programs > GeoMedia Object Diagrams Transportation Manager > Developer Documentation > GeoMedia Transportation Object Diagrams. GeoMedia Online only Workflow diagrams for programmers. Available online Transportation in .pdf format at Start > All Programs > GeoMedia Workflow Transportation Manager > Developer Documentation > Diagrams GeoMedia Transportation Workflow Diagrams. Visit our web site at http://support.intergraph.com/Documentation.asp for the latest version of these documents. 1-3
  15. 15. Working with GeoMedia Transportation Manager Document Conventions Typeface Conventions Used in the Documents ALL CAPS Keyboard keys. If keys are separated by a comma, press them in sequence. For example: ALT, F5. If they are joined by a plus sign, press them at the same time. For example: CTRL+z. Bold An item in the graphical interface, such as the title unserifed of a dialog box or a tool. Paths through menus use type right angle brackets between items you select. For example: Select File > Open to load a new file. Courier Information you type. type For example: Type original.dat to load the ASCII file. Italic type A document title, the first occurrence of a new or special term, folder and filenames, or information about what the software is doing. 1-4
  16. 16. Introduction to Linear Referencing The purpose of this chapter is to outline the basic concepts behind the linear referencing capabilities of GeoMedia Transportation Manager. Both single-level and Multilevel linear referencing systems (LRSs) are described in some detail. Lastly, the various LRS analysis and maintenance tools are described. What is Linear Referencing? Linear Referencing is simply the tracking and analysis of data that is associated with locations along a linear network. Some road transportation examples include tracking the location of and condition of signage, the condition of pavement, and the location and severity of accident occurrences. The biggest uses of linear referencing are Asset Tracking and Asset Analysis. Asset Tracking primarily encompasses the following four items: • What, where, and when of the assets (for example, a pothole at kilometer post 41.7 along Route 66, reported June 6th, 2002) • Asset conditions (for example, a stretch of pavement with rutting and cracking) • Incidents along the network (for example, a traffic accident) • Activities along the network (for example, construction projects) Asset Analysis includes such activities as “hot- spotting” (finding areas with an unusual density of a given type of problem) and cross-discipline analysis (for example, cross analyzing areas that have both run- off-the-road accidents and no guardrails). This type of analysis can be important for any number of areas, including the following: • Protecting the public (for example, finding areas of high-density accidents and finding the common contributing factor) • Optimizing usage of assets (for example, locating areas with both high volume and low number of lanes in order to identify areas of congestion) • Optimizing budget usage (for example, locating the areas with the most traffic and the worst pavement conditions to be first priority for resurfacing) 2-1
  17. 17. Working with GeoMedia Transportation Manager Linear Referencing and GeoSpatial Technology The main impetus to merge linear referencing with geospatial technology can be summed up simply: it is often desirable to view location data on a map. It also opens up a lot of other analysis capabilities, such as summing up data within an area feature (for example, the kilometers of rail track that require maintenance within a given jurisdiction) or finding data within a proximity of linearly referenced data (for example, finding residences within a buffer zone of a construction project). Using GeoMedia Transportation Manager is not the only way to merge linear referencing and geospatial technology, but it is certainly the easiest. GeoMedia Transportation Manager enables you to create map features, including pavement conditions, accident data, and average daily traffic. This kind of information will help you plan improvements for deteriorating assets, will identify where your organization is spending its money, and will provide critical information clearly and accurately to all participants involved in your projects. GeoMedia Transportation Manager increases the value of your data by turning it into business-critical, decision-support information. 4.1 3.2 3 2 1.8 Hwy 6 0.9 The preceding diagram shows a portion of road on the left and its geospatial representation on the right. The road has kilometer posts that indicate cumulative linear measures along the road. It also has a road name, Highway 6 in this example. A section of fencing along the road is also shown in both the left and right views. Based on the kilometer posts, it can be determined in the field that this stretch of fence runs along Highway 6 from kilometer measure 2.0 to 2.6. On the geospatial side, we have three linear features, known as LRS Linear Features, that will all have a road name and begin and end measure attribution. These LRS Linear Features are the backbone of the LRS and are used in automating the mapping of linearly referenced data, such as this stretch of fencing, onto our map view. 2-2
  18. 18. Introduction to Linear Referencing Of course, this mapping of linearly referenced data does not have to be automated. Without GeoMedia Transportation Manager, you can estimate where kilometer measures 2.0 and 2.6 are along the road, and then you can digitize a linear feature between these two points and along the road. This is not too hard for a few features, but what if you have a tabular report for hundreds or thousands of linearly referenced items that you want to map? With GeoMedia Transportation Manager, all of these items can be mapped with a single command. The methodology used by GeoMedia Transportation Manager to do this bulk mapping of linearly referenced tabular data is called Dynamic Segmentation (or linear geocoding). This methodology interpolates the location of linearly referenced data along the LRS Linear Features by making use of the road (or rail, ferry line, and so on) name and measurement attributes stored on those features. LRS Linear Features and Event Data As mentioned before, LRS Linear Features are the backbone of the LRS. But working with the linearly referenced tabular data, known as Event Data, is the whole reason for building the LRS in the first place. Although the data structures of these two components are described in detail in Appendix B: GeoMedia Transportation LRS Data Structures, we will provide a brief summary here of what is known as traditional, or single-level, LRS. We will address Multilevel LRS (MLRS) in the next section. The LRS Linear Features represent the network itself. Each LRS Linear Feature table is a linear feature class that has the following fields: • ID – This is a long integer value that uniquely identifies each feature within the table. • LRSKeys1-4 – This is one to four fields that together define the “route” that this feature belongs to. • StartMeasure – This is a numeric value that contains the measurement value for the beginning of this feature. • EndMeasure or Duration – This is a numeric value that contains either the measurement value for the end of this feature or the length measurement for this feature. • BeginMarker (optional) – This field stores a name for the beginning position of this feature. This is referred to as an internal marker. • EndMarker (optional) – This field stores a name for the end position of this feature. This is referred to as an internal marker. • ReversedGeometry (optional) – This Boolean (True/False) field declares whether the GeoMedia Transportation Manager software should treat this linear feature as if (False) or as if its digitizing direction were reversed and its beginning were its end, and vice- versa (True). 2-3
  19. 19. Working with GeoMedia Transportation Manager The Event Data represents the linearly referenced data. Note that Event Data can either be point data (occurring at just one spot on the linear network) or linear data (occurring at a span of distance along the linear network). Each Event Data table is (usually) a non- graphic table that has the following fields: • ID – This is a long integer value that uniquely identifies each record within the table. • LRSKeys1-4 – This is one to four fields that together define the “route” that this record lies along. • Measurement data (pick one of the following options) - Measure Option – For point event data, this consists of one numeric Measure field that indicates the relative location of the point event record on the “route” defined by the LRS Key fields. For linear event data, this consists of two numeric fields: a StartMeasure field and an EndMeasure field. These define the relative location of the start and end points of the linear event record on the “route” defined by the LRS Key fields. - Marker Offset Option – For point event data, this consists of a Marker name field and a numeric Offset distance field. The point event data is located by first locating the marker and then by adding the offset distance to that location. For linear event data, there are two Marker fields and two Offset fields defining the start and end of the linear event record. - Coordinate Option – For point event data, this consists of two fields which, depending on the referenced Coordinate System File, may by either projected coordinates (for example, Northing & Easting) or geographic coordinates (Latitude & Longitude). For linear event data, there are four fields defining the coordinates for both the start and the end of the linear event record. - Duration Option – This is a slight variation on the Measurement Option and only applies to linear event data. It consists of a StartMeasure field and a Duration (or Length) field that together define the relative location of the record along its “route.” • Other Attributes (optional) – These are optional, but they are also the whole reason for doing linear referencing. For bridge events, these will store bridge data; for accident events, they will store accident data; and for pavement events, they will store pavement data. Optional components of the LRS that we have not discussed as yet are the External Markers. External Markers mark points along the network just like the Internal Markers discussed earlier, but these are not bound to just the beginning and end of LRS Linear Features. External Markers can occur anywhere along the LRS network and are functionally equivalent to point event data using the Measure option. They are useful for modeling milestones and monuments that are commonly used to measure locations from. They can be used, along with Internal Markers, to locate event data using the Marker Offset option. 2-4
  20. 20. Introduction to Linear Referencing Each External Marker table is (usually) a non-graphic table that has the following fields: • ID – This is a long integer value that uniquely identifies each record within the table. • LRSKeys1-4 – This is one to four fields that together define the “route” that this record lies along. • Measure – This is a numeric field that indicates the relative location of the External Marker on the “route” defined by the LRS Key fields. • MarkerName – This field stores a name for this Marker. Detailed information on how to create a LRS Linear Feature class is provided in the “LRS Data Preparation Workflows” chapter. Information on at least one way to populate Event Data and External Marker tables is provided in the “Working with the Insert LRS Event Command” chapter. Multilevel Linear Referencing Systems (MLRS) GeoMedia Transportation Manager and GeoMedia Transportation Analyst now support Multilevel LRSs (MLRS) as well as the traditional, single-level LRSs. Multilevel LRS has been a topic of discussion since at least the early 1990s and the original NCHRP (National Cooperative Highway Research Program) 20-27 study. The Multilevel LRS model that Intergraph uses is known as the GeoTrans model and is derivative of the NCHRP 20-27 model. Since the inception of the concept of Multilevel LRS, there have been numerous implementations and attempted implementations. The reason for the interest is very understandable. This kind of model addresses a variety of problems that are common to almost all transportation agencies, which raises the question as to why this kind of model is not more common. First, let’s summarize some of the problems a Multilevel LRS solves, and then we will explore why these models are not in use everywhere. Multiple Linear Referencing Methods Perhaps the key issue addressed by Multilevel LRSs is the need to support multiple Linear Referencing Methods (LRMs). Most transportation agencies have various sub departments and external sources that collect data about their transportation network using a variety of different measurement methods and sometimes different road- or rail-naming conventions. A few example LRMs are shown here: 2-5
  21. 21. Working with GeoMedia Transportation Manager County Border State Border 175 Main St. Route 50 Main St. 87.60 mi Address Range: 100 to 200 State Cumulative Street Address with Spruce Ave. with Elm Ave. County Border Intersection Intersection State Border Route 50 Main St. 5.4 mi 200 ft East County Cumulative Marker Offset Support of these different LRMs is key to being able to compile the data collected by these different methods for analysis. For example, if accidents are located by GPS and guardrail inventory is located by milepost, then you would need to be able to use these different LRMs together in order to locate an accident in which a car runs off the road where there is no guardrail. Multiple Geometric Representations Another issue that can be addressed by Multilevel LRSs is the need that many transportation agencies have to support more than one geometric representation of their network. One case for this is where different levels of generalization are used for different map products. Agencies would like to be able to use the same event data (also known as distributed attribute data) against different geometric representations, depending on whether they are doing large-scale or small-scale analysis. 2-6
  22. 22. Introduction to Linear Referencing A second common use case for multiple geometric representations is where some of the data comes from a regional agency and some of it comes from one or more local agencies. There may be considerable overlap of the data coverage, but there may also be many roads covered by the local data that are not covered by the regional data. For some analyses, the user will want to see all of the local roads; but for others, he or she will only want to use the major roads. Without a Multilevel LRS, users have to duplicate 100% of their LRS data maintenance efforts for each geometric representation that they want. And even then, they are not assured that each LRS is in sync with the other and will give similar analysis results. Agencies want to be able to easily switch back and forth between geometric representations without worrying if this will affect the validity of their analysis. This is possible with Multilevel LRSs. 2-7
  23. 23. Working with GeoMedia Transportation Manager Event Location Stability One of the toughest challenges facing managers of transportation information is how to handle the effects of changes that are made in the transportation network over time. These changes include road-name changes, realignments, recalibrations, and so on. To illustrate these effects, we have an example of a small piece of a network with some point and linear event data associated with it. We will say that the point events represent accident locations along a road and that the linear event represents pavement conditions. This is our “before” picture: Before network changes 0 5 7 11 13 18 Now let’s see what happens to our data when our road gets realigned and recalibrated. Because dynamic segmentation is an interpolation based on the road names, measures, and geometry, all of these changes can cause our linearly referenced event data to shift locations with a traditional LRS. In this case, these errors show accident data where accidents never happened, and they show pavement conditions for a now-abandoned piece of roadway as if the data relates to a new stretch of road. After network changes – with Single Level LRS 0 5 7 11 13 18 10 12 17 Now let’s look at this same example using the GeoTrans data model, which has some special features to address this particular problem. Here we see that our accidents and pavement conditions do not shift. Furthermore, these pavement conditions show up only on the segments of the road on which this data actually occurred – even with linear event data. After network changes – with GeoTrans model 0 5 7 11 13 18 10 12 17 2-8
  24. 24. Introduction to Linear Referencing Data with incorrect locations is bad data and can lead to bad decisions. So, the desired effect is that we should see those events, and only those events, that pertain to the current version of the network. This should work for both point and linear events. GeoMedia Transportation Manager and the GeoTrans data model make this possible. To take this further, many agencies would like to be able to look at the state of their networks for a specific time period and to see only those events that pertain to those networks as they existed at that specific time. When GeoMedia Transportation Manager is used in conjunction with GeoMedia Transaction Manager, this type of temporal analysis and temporal data management is made easy. This is discussed in more detail below and in the “Working with Multilevel LRSs” chapter. Why do so few transportation agencies use MLRS? In the last few sections, we have seen a few of the important benefits (there are others) of using Multilevel LRS. So why are most transportation agencies still using traditional, single-level LRS? Part of the reason is that implementations have been costly because of the lack of availability, until now, of an off-the-shelf solution. Implementations have had to be custom. The toughest part of these custom implementations has not been analysis, but rather it has been data maintenance. As we will see in the next section, the data in the GeoTrans model is spread over multiple, connected layers. Because of this, a single change affects multiple layers and the relationships between those layers. Because of this, it is understandable that the hardships associated with Multilevel LRSs have been too high a hurdle for most agencies to overcome. GeoMedia Transportation Manager has overcome these obstacles by providing a tool that is available off-the-shelf that integrates the benefits of Multilevel LRS with the tools used to maintain and make use of it. So GeoMedia Transportation Manager, while also supporting traditional, single-level LRS, also has a complete set of tools for building, maintaining, and analyzing a Multilevel LRS. These tools are designed to take much of the complexity out of using this powerful model, while still giving all of the benefits. This will allow for better, more accurate, and more complete analyses of transportation data and will make the promise of Multilevel LRS a reality. GeoTrans Data Model In this section, we review the development and structure of the GeoTrans data model that is the core of our MLRS solution. As mentioned before, the GeoTrans data model is derivative of the NCHRP 20-27 model. However, we have made some tweaks to improve event location stability and temporality and to allow for more flexible segmentation. Before we get into the GeoTrans data model let’s start by looking at a logical representation of the traditional, single-level LRS. A single-level LRS consists of an LRS linear feature class with geometry, name, and measurement data. This LRS linear feature class is the foundation for linearly referencing any number of event tables. The LRS 2-9
  25. 25. Working with GeoMedia Transportation Manager Linear feature class and the event tables are “joined” via dynamic segmentation. This model works fine for a static network with just one LRM and just one geometric representation of the network and has been the state of the art for years. Event Event Event 1 2 N LRS Now, what do we do if we have a network that changes over time (road-name changes, realignments, and so on), if we have more than one LRM, or if we have more than one geometric representation of our network? The theory behind Multilevel LRS is to abstract out into separate entities those parts of the network that change independently. Towards that end, we have abstracted the route naming and measurement part into an LRM layer that can contain any number of LRMs. We have also abstracted the geometric representation part into a Geometry layer that can contain any number of physical representations of our network. We have tied both of these to a Linear Datum. The Linear Datum acts as a non-changing anchor that these other layers can tie to. A unique feature of the GeoTrans model is that the Linear Datum records can neither be edited nor deleted. They can only be added to when there are new roads or realignments. This permanence is, as we shall see, the key to Event Location Stability. Event Event Event Event Event Event Event Event Event 1/1 1/2 1/N 2/1 2/2 2/N N/1 N/2 N/N Event Data LRM LRM LRM 1 2 N Linear Referencing Methods Linear Datum Datum Cartographic Geom Geom Geom Representations 1 2 N So from a practical stand point, how do we relate the individual LRMs and Geometries back to the Linear Datum? When we need a one-to-one or a one-to-many relationship in a database, we use a Join where one field in one table exactly matches a field in another table. However, if we do not want to force our model to have all geometries and LRMs segmented identically, then what we have is a many-to-many relationship. This is handled by having an intermediate table to store the relationship. The ability to have completely independent segmentation is a unique feature of the GeoTrans data model. We accomplish this by not using a standard many-to-many join, but rather by using dynamic segmentation to establish our relationships. 2-10
  26. 26. Introduction to Linear Referencing In the following diagram, we show the intermediate tables that store this many-to-many relationship. We call these cross reference tables (G-D xRef refers to Geometry to Datum cross reference, and L-D xRef refers to Datum to LRM cross reference). The diagram also shows the multilevel dynamic segmentation that relates each of these tables together. This complexity is handled for you by the software so that you get the benefits of the model without the extra trouble. LRM Event BegMeas EndMeas Attributes Key(s) LRM Rev LRM LRMID BegMeas EndMeas Key(s) Geom Datum LRM L-D xRef ID BegMeas EndMeas ID BegMeas EndMeas Linear Datum DatumID Length Description Geometry Datum G-D xRef ID BegMeas EndMeas ID BegMeas EndMeas Geometry GeomID BegMeas EndMeas Geometry Another key part of the model pertains to our Event Location Stability methodology. By way of contrast, we will describe two common alternative methods that some have used to accomplish this same thing. The first alternative method is sometimes referred to as Permanent Event Geometry, which simply means storing geometry created during dynamic segmentation permanently with the event data. The upside of this methodology is its simplicity. One downside is that it only works well if you have only one geometric representation and you never expect to update it with newly collected geometry. Another downside is that it does not handle temporality well. If a road gets realigned, this method will still show event data along the old alignment that no longer exists. The second alternative method is sometimes referred to as Cascading Edits. This method develops database triggers that will change the measures of all event data associated with an LRS any time the LRS changes. The upside of this method is that the custom code it contains gives a lot of flexibility. However, it has several downsides. First, as in most transportation agencies, there could be a performance issue when a large number of tables are affected. Second, it assumes that all event tables are stored in the central database and thus are accessible to these triggers. Third, this problem is fairly difficult to implement for 2-11
  27. 27. Working with GeoMedia Transportation Manager events associated with the segment of the LRS that is actually changed. Lastly, it has the additional problem that once the measures are changed, they no longer are in the correct location in relation to the “old” version of the LRS. This creates an event location stability problem if you try to look at a temporal view of the data the way it once was. Thus this method is ill-suited for temporal analysis. The method we have implemented in the GeoMedia Transportation products and the GeoTrans data model is called Event Registration. The downside of this method is that it requires users to do a one-time Event Registration step whenever they bring in new event data. The upside is that it has none of the downsides described above. The Event Registration step is done with the LRS Event Transform command (see the “Working with the LRS Event Transform Command” chapter). One of the options of this command is to convert LRM-based names and measures on Event tables to Datum-based names and measures. Once this simple step is done, this event data can be used regardless of how the network changes over time. Road names can change, routes can be recalibrated, and realignments may occur – but the event data will still locate correctly. The following figure shows the complete GeoTrans logical model. Note that this model shows some events as “LRM” Events and others as “Datum” Events. The Datum Events are those that have gone through Event Registration and thus will receive the benefit of Event Location Stability. Also shown on this diagram are the two types of external markers now supported by the GeoTrans data model. The ones labeled “LRM” Markers are the same as those used by traditional, single-level LRS. The ones labeled “Datum” Markers are LRM Markers that have gone through Event Registration and, therefore, have the same location stability as Datum Events. 2-12
  28. 28. Introduction to Linear Referencing Event Event Event 1/1 1/2 1/N Event Event Event 2/1 2/2 2/N ‘LRM’ Events Event Event Event N/1 N/2 N/N LRM LRM LRM 1 2 N ‘LRM’ Markers xRef xRef xRef 1 2 N Event D/1 Event Linear Datum D/2 ‘Datum’ Markers Event D/N ‘Datum’ Events xRef xRef xRef 1 2 N Geom Geom Geom 1 2 N Another important consideration in the design of this model is support for temporality. Many agencies want to not only be able to analyze their transportation network as it is – but also how it was (for trend analysis) or how it might be (for design and planning purposes). When you use the GeoMedia Transportation products with GeoMedia Transaction Manager, you can automatically store historical versions of the network as it is being edited in order to represent the latest changes to your network. Likewise, you can model designs for future changes to the network without destroying the current representation. With events that have been registered, you can view both the network and linearly referenced event data correctly for any time for which you have data. (Please note that GeoMedia Transaction Manager is not required in order for you to use the GeoMedia Transportation products, but without it only current network analysis is possible.) More details about the GeoTrans data model are discussed in Appendix B: GeoMedia Transportation LRS Data Structures. 2-13
  29. 29. Working with GeoMedia Transportation Manager Linear Referencing Analysis This section provides brief descriptions of the major LRS Analysis tools provided by GeoMedia Transportation Manager. Detailed instructions on how to use each of these commands is provided elsewhere. Display LRM – This command creates an LRM query and works with either single-level or Multilevel LRSs. It works in conjunction with the LRS Metadata command, which is used to populate the choices the user has. For an MLRS, those choices are which LRM and Geometry to use. For single-level LRSs, the choice is only which single-level LRS to use. In both cases, the resultant query carries along metadata which simplifies the use of many of the other commands. When this query is used as the LRS Feature Class, the appropriate LRS Properties are automatically filled in. For more information see the “Working with the Display LRM Command” chapter. Dynamic Segmentation – This command, which has already been referred to above, takes linearly referenced tabular data and creates a graphic query class from it that can be viewed in the map view. This lets you visualize your organization's inventory of assets more clearly than by simply reviewing tabular data. For more information see the “Linear Referencing” chapter in Working with GeoMedia or Working with GeoMedia Professional. Note: The Dynamic Segmentation command is now located on the GeoMedia Professional menu bar under Analysis. LRS Event Overlay – This command compares two different Event Data tables and calculates intersections, differences, or unions of the two tables and presents the results as a graphic query class that can be viewed in the map window. An example of this is to map all the locations with run-off-the road accidents and no guard rails. For more information see the “Working with the LRS Event Overlay Command” chapter. Resolve LRS Event Overlaps – This command takes a single linear Event Data table and provides a very user-definable method for removing overlaps in the data. For example, in a table of pavement conditions you may have many overlapping records, but you may want to only see the most current pavement condition records. For more information see the “Working with the Resolve LRS Event Overlaps Command” chapter. LRS Precision Location – This command allows you to get real-time LRS locations of your cursor location in the map view. It also allows you to use key-ins of LRS locations to place points in the map view. These points may just be used for orientation, but they also can be used for placing vertices of new geometry. For more information see the “Linear Referencing” chapter in Working with GeoMedia or Working with GeoMedia Professional. Note: The LRS Precision Location command is now located on the GeoMedia Professional menu bar under Tools. 2-14
  30. 30. Introduction to Linear Referencing LRS Event Conversion – This command allows you to convert the measurement portion of your event data from one measurement option to another (these options were described earlier). This can allow you, among other things, to convert event data collected in a number of ways to a single measurement method for more consistent reporting. For more information see the “Working with the LRS Event Conversion Command” chapter. Convert Intersection-referenced Events – This command takes intersection-referenced event data and converts it into marker-offset event data that is compatible with the GeoMedia Transportation products. It has a special tool for handling the ambiguity associated with intersection-referenced event data associated with roads that cross more than once. This command works in conjunction with the Create Intersection Markers command. For more information see the “Working with the Convert Intersection Referenced Events Command” chapter. LRS Event Generation – This command provides you with a number of ways to generate event data at various defined points along the LRS network. This comes in handy for both annotation and aggregation workflows. For more information see the “Working with the LRS Event Generation Command,” “LRS Annotation Workflows,” and “LRS Analysis Workflows” chapters. LRS Keys for Coordinate Events– This command will take Event data that has coordinate data but no LRS Key data and add the LRS Key data to it. This will make this kind of Event Data, commonly collected using GPS instruments, usable with the other analysis commands, such as Dynamic Segmentation and LRS Event Overlay. For more information see the “Working with the LRS Keys for Coordinate Events Command” chapter. Routes and Sections to LRS – This command takes the two component classes from an ArcRoute system (Routes and Sections) and creates a single query of an LRS class that is usable with the other commands within GeoMedia Transportation Manager. For more information see the “Working with the Routes and Sections to LRS Command” chapter. Insert LRS Event – This command allows you to interactively create event data by clicking on the map view to define LRS key, begin measures, and (for linear events) end measures. This will allow you to create event data via “heads-up” digitizing. For more information see the “Working with the Insert LRS Event Command” chapter. LRS Event Transform – This is an MLRS command that can transform an event feature class in any of the following ways: • LRM-based to Datum-based Event feature class (Event Registration) • Datum-based to selected LRM-based Event feature class in the same linear referencing system • Source-LRM-based to target LRM in the same linear referencing system For more information see the “Working with the LRS Event Transform Command” chapter. 2-15
  31. 31. Working with GeoMedia Transportation Manager Linear Referencing System Maintenance This section provides brief descriptions of the major LRS Maintenance tools provided by GeoMedia Transportation Manager. Detailed instructions on how to use each of these commands is provided elsewhere. A good overview of LRS maintenance is provided in the “LRS Data Preparation Workflows” chapter. LRS Metadata Definition – This command provides the capability to define and modify LRS Metadata for either single-level or Multilevel LRSs. This allows a one time identification of the key tables and fields associated with the LRS so that others can make use of this definition without duplication of effort. This command works closely with the Display LRM command in order to simplify the use of the various LRS Analysis and Maintenance commands. For more information see the “Working with the LRS Metadata Definition Command” chapter. Interactive LRS Calibration – This command can be used to name and calibrate (that is, populate measure values in) LRS features one route at a time. For more information see the “Working with the Interactive LRS Calibration Command” chapter. LRS Calibration – This command can be used to calibrate (that is, populate measure values in) LRS features an entire feature class at a time. For more information see the “Working with the LRS Calibration Command” chapter. LRS Validation – This command can be used to validate that a linear feature class is also a working LRS feature class that will provide accurate results. It queues up errors for easy correction. For more information see the “Working with the LRS Validation Command” chapter. Reformat Linear Collections – This command can be used to repair some of the problems common to data sets containing geometry collections. It assures that components of geometry collections are in order and have correct and consistent digitizing directions. This helps assure an LRS that provides correct analysis results. For more information see the “Working with the Reformat Linear Collections Command” chapter. Create Intersection Markers – This command creates an Intersection Markers feature class for an input LRS feature class. The Intersection Markers feature class will be a point feature class that represents all valid intersections in the input LRS feature class. This command is used in conjunction with the Convert Intersection-referenced Events command. For more information see the “Working with the Create Intersection Markers Command” chapter. Create Intersections and Midblocks – This command creates two feature classes. The Intersection feature class covers the portions of the network within a user-specified distance of each valid intersection and has attribution identifying associated roads. The Midblock feature class shows that portion of the network in between these Intersection features and also includes identifying attribution. Both of these feature classes are very useful in aggregation workflows. For more information see the “Working with the Create Intersections and Midblocks Command” chapter. 2-16
  32. 32. Introduction to Linear Referencing Insert LRM Segment – This command is a special MLRS command to simplify the task of inserting new features into a Multilevel LRS dataset. For more information see the “Working with the Insert LRM Segment Command” chapter. Split LRM Segment – This command is a special MLRS command to simplify the task of splitting features in a Multilevel LRS dataset. For more information see the “Working with the Split LRM Segment Command” chapter. Redigitize LRM Segment – This command is a special MLRS command to simplify the task of redigitizing features or portions of features in a Multilevel LRS dataset. For more information see the “Working with the Redigitize LRM Segment Command” chapter. Merge LRM Segments – This command is a special MLRS command to simplify the task of merging features in a Multilevel LRS dataset. For more information see the “Working with the Merge LRM Segments Command” chapter. Delete LRM Segment – This command is a special MLRS command to simplify the task of deleting features in a Multilevel LRS dataset. For more information see the “Working with the Delete LRM Segment Command” chapter. Output Linear Datum – This command provides the capability to display the linear datum graphically. It has special abilities to show the entire datum even if the entire datum is not represented in any one geometric definition. This command is primarily used by the two LRS Conflation commands. For more information see the “Working with the Output Linear Datum Command” chapter. Interactive Multilevel LRS Conflation – This command can be used to update an existing MLRS with new data from a separate linear feature class. In the Update mode of this command, the user identifies the related portions of both the new and existing data and which LRM and/or Geometry tables to update (while maintaining Linear datum definitions). In Insert mode, the user needs only to identify the pertinent potions of the new data and what LRM and/or Geometry tables to add to. For more information see the “Working with the Interactive Multilevel LRS Conflation Command” chapter. Multilevel LRS Conflation – Like the Interactive Multilevel LRS Conflation command, this command can be used to update an existing MLRS with new data from a separate linear feature class. The difference is that instead of interactively identifying related portions of new and existing data, this command makes use of the Links database, which can be populated using GeoMedia Fusion. Even without GeoMedia Fusion, this command is useful for converting single-level LRSs into MLRSs. For more information see the “Working with the Multilevel LRS Conflation Command” chapter. Multilevel LRS Validation – This is an Oracle-only command used to validate the MLRSs. It works in conjunction with the LRS Validation command to find MLRS data errors. For more information see the “Working with the Multilevel LRS Validation Command” chapter. 2-17
  33. 33. Working with GeoMedia Transportation Manager 2-18
  34. 34. Introduction to Working with Multilevel LRSs This chapter provides general guidance for working with Multilevel LRSs. The focus is on how to make use of a Multilevel LRS after its initial creation. It covers using this kind of LRS for analysis as well as the maintenance of the LRS. Therefore, this chapter is broken into two major sections: LRS Analysis using a Multilevel LRS • Maintaining a Multilevel LRS Before reading this chapter, it is recommended that you first read the “Multilevel Linear Referencing Systems (MLRS)” section of the “Introduction to Linear Referencing” chapter for a basic description of the GeoTrans Multilevel LRS data model. Also recommended is the “Single Level to Multilevel LRS Conversion Workflow” chapter for help in initial creation and population of a Multilevel LRS. LRS Analysis Using a Multilevel LRS In this section, topics pertaining to performing analysis with a Multilevel LRS are examined. The topics to be explored are as follows: • Intelligent LRS features • Region IDs • Event location stability • Multiple LRM Support • Temporal analysis Intelligent LRS Features Perhaps the key concept in using Multilevel LRSs is the role of intelligent LRS features. These features are created using the Display LRM command (see the “Working with the Display LRM Command” chapter) in conjunction with the LRS Metadata Definition command (see the “Working with the LRS Metadata Definition command” chapter). The LRS Metadata Definition command defines the tables that make up a Multilevel LRS and which fields in those tables play which roles. The Display LRM command uses that metadata to display an intelligent LRS feature class using the user’s selected LRM/Geometry combination. This intelligent LRS feature class can then be used in any command that asks for “LRS Features.” The benefit is that intelligent LRS feature classes have extra information tagged 3-1
  35. 35. Working with GeoMedia Transportation Manager to them so that all LRS Model information is automatically filled out when it is used in LRS analysis. Use the Display LRM command to create an intelligent LRS feature class. Use Display LRM’s intelligent feature class with any command that asks for LRS features. LRS model and properties are automatically filled in. 3-2
  36. 36. Introduction to Working with Multilevel LRSs Region IDs A second key concept is Region IDs. One of the options given in the LRS Metadata Definition command (see the “Working with the LRS Metadata Definition Command” chapter) is to define Region IDs. This is a way of subdividing your network into logical units. This is usually done using political boundaries. As shown in the previous example, the Display LRM command (see the “Working with the Display LRM Command” chapter) allows you the option to filter your output by these region IDs. This provides a convenient way to minimize the amount of data you are working with at any particular time and thus to improve performance. Region IDs are made even more useful by the ability to edit the Region settings of an intelligent LRS feature. This is done as with any query using the Query Properties dialog box. This means the Display LRM query does not have to be re-created as you move around to work with one region to another. Also, due to the dynamic pipe architecture of the GeoMedia products, queries based on this intelligent LRS feature class will update to reflect the new region settings. Region IDs can minimize the amount of data being used and can improve performance. 3-3
  37. 37. Working with GeoMedia Transportation Manager Region ID settings can be edited. Analyses based on the intelligent LRS feature will update. Event Location Stability The GeoTrans Multilevel LRS data model is designed to provide for event location stability. This topic is introduced in the “Event Location Stability” section of the “Introduction to Linear Referencing” chapter. This is an optional capability. The basic principle is that route names, measures, and even geometric representations are volatile in that they may change over time. Therefore we recommend that you convert your event data’s location information to a non-volatile format. We refer to this non- volatile format as a Datum based location reference. LRM LRM Linear LRM LRM Datum LRM LRM The Linear Datum is the foundation of Intergraph’s MLRS. 3-4
  38. 38. Introduction to Working with Multilevel LRSs This location format conversion is implemented via a method referred to as Event Registration using the LRS Event Transform command. Simply choose the LRM to Datum transform mode when using this command. For linear events, also choose any attributes that you want to be proportioned in case events need to be split. The LRS Event Transform command is used to perform Event Registration. This is a one-time process. The resultant converted event feature class should be saved as the permanent version of the event table. That’s it! Your data has been protected. To simplify usage of this converted event data, the commands that use event data have been modified to use either LRM based or Datum based event data. If all of your data is converted to a Datum based location format, you can use all of your event data together. So, for instance, guardrail data originally collected with one LRM can be analyzed versus accident data originally calculated using another LRM using the LRS Event Overlay command. Event data that has been registered can be used directly with all of GeoMedia Transportation’s commands that use event data. 3-5
  39. 39. Working with GeoMedia Transportation Manager Multiple LRM Support Although Event registration to a Datum based location reference is the recommended way to work with event data collected using various LRMs, it is not the only way. The LRS Event Transform command can convert event data directly from one LRM to another. Simply choose the LRM to LRM transform mode when using this command. For linear events, also choose any attributes that you want to be proportioned in case events need to be split. But note that by using this method, the benefits of event location stability are not attained. The LRS Event Transform command can convert event data between LRMs. Temporal Analysis The GeoMedia Transportation products are designed to be able to be used either with or without GeoMedia Transaction Manager. One can reap almost all of the benefits of using a Multilevel LRS without using GeoMedia Transaction Manager, with one exception. That exception is temporal data capture and analysis. GeoMedia Transaction Manager gives you the ability to model your network as it changes over time and then to use it for analyses such as evaluating the cost/benefit of various roadway improvement strategies or performing trend analysis for congestion, safety, and so on. This subsection addresses temporal analysis. Temporal data capture is covered later in this chapter. In depth coverage of setting up and using GeoMedia Transaction Manager is covered in the Working with GeoMedia Transaction Manager document. This is only meant as an overview. 3-6
  40. 40. Introduction to Working with Multilevel LRSs Regarding temporal analysis, there are two tools for reviewing data that represents a given time or time period. The first tool uses a “Valid Time filter.” This can be set using the Set Valid Time Options button on the Transaction Manager Settings dockable control, shown below. Simply set the Valid Time filter date to the date you want to see, and all the features in that connection will display the portion of your data that represents that date. You can set which date you wish to view via the Transaction Manager Settings control. The second tool is the Temporal Query command. This tools lets you pick a specific date as did the Valid Time filter, but it also has the option to pick a time range. It has two other differences. First, the Temporal Query command works on one feature class at a time as opposed to an entire connection. Second it can be run multiple times. That means you might want to show your road network as it was between 1995 and 2000 in one color and between 2000 and 2005 in another. The Temporal Query command can be used to see a given date or a time range 3-7
  41. 41. Working with GeoMedia Transportation Manager Maintaining a Multilevel LRS In this section, topics pertaining to maintaining a Multilevel LRS are examined. The topics to be explored are as follows: • Temporality During Editing • Intelligent Editing • Interactive Multilevel LRS Conflation • Bulk Multilevel LRS Conflation • Calibration • Validation • Routing • Production tables Temporality During Editing This subsection covers how to use GeoMedia Transaction Manager to capture real-world history while you are editing. In-depth coverage of setting up and using GeoMedia Transaction Manager is covered in the Working with GeoMedia Transaction Manager document. This is only meant as an overview. GeoMedia Transaction Manager is designed to do several things, two of which are very pertinent to editing transportation networks. The first is long-term transactions. That means that while you are editing, your revisions are invisible to the normal user up until the point you have accepted them and are ready to reveal them to the general user population. You also have the option to discard some or all of your revisions. This way any “mistakes" can be made and caught before affecting general system users. The second pertinent capability of GeoMedia Transaction Manager is capturing temporal history. By default it captures transactional temporal history. This means you can see what your database looked like at any point in time. However, much more important to transportation users is the optional ability to capture real-world temporal history. This means you can see the database’s representation of the world as it existed at any point in time. It can also be used to capture future representations of the world. Both of these capabilities are very easy to use. The basic workflow is as follows: 1. Create a Revision Set (start an editing session). 2. Edit as usual. 3. Commit or Discard your changes, and Retire your Revision Set. 3-8
  42. 42. Introduction to Working with Multilevel LRSs GeoMedia Transaction Manager is used for the first and third steps. The second step is the topic of the rest of this chapter that follows this subsection. You can think of GeoMedia Transaction manager as bookends that come just before and just after your normal editing. The first step, creating a revision set, is very easy. Just use the New option of the Revision Sets command. The New Revision Set dialog box, shown below, has several key parts. The Name and Description entries can be whatever you want and are usually used to describe the types of edits you are making. The Options section tells GeoMedia Transaction Manager whether you are using Pessimistic or Optimistic transactions. A full description of these choices is in the Working with GeoMedia Transaction Manager document, but Pessimistic is the correct choice in most situations. The Valid from date is the date that you want your edits to represent. So, for example, if you are editing your network to show a curve realignment that went into service on 7/7/2003 and will stay in service indefinitely, you would fill out the dialog box as shown below. If you know the date your changes will go out of effect, then use an actual date for the Valid until date as opposed to Valid until Modified. Lastly, but very importantly, if your edits are to represent some real-world change, you would check Capture Valid Time for Updates and Deletes, as shown here. However, if your edits are just to correct data, then you would not check either of these. Note that Inserts are always stamped with the Valid from/Valid until dates, so make sure to set these dates appropriately regardless of which capture Valid Time options you choose. The New Revision Set dialog sets the parameters for editing with GeoMedia Transaction Manager. 3-9

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