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DOT Develops Robust Enterprise Geospatial Repository

Geodatabase Design Tools

One of the first tasks in customizing the UNETRANS model was identifying and learning to use the applicable tools. Edits to a geodatabase (whether a personal or ArcSDE geodatabase) can be made through the graphical user interface and wizards in ArcCatalog. However, VDOT realized that the complexity and interconnection of the data model elements would make it difficult to manage and document changes made outside the data model itself so VDOT decided to use some additional tools.

  • Visio Professional 2002 with Esri CASE Tools extension
  • Geodatabase Diagrammer
  • Geodatabase Designer
  • SDELoader tool
  • EditorID tool

Visio Professional 2002 with Esri CASE Tools Extension

The UNETRANS UML template data model is distributed in Microsoft Visio file format (VSD). The version of Visio used is important because not all Visio versions support the Esri XML Export CASE Tools extension. Visio Professional 2002, currently used by VDOT, allows export of the representation of the model in XML and its object classes to a file that the ArcCatalog Case Schema Creation wizard can use to generate the database model structure to a selected geodatabase. To cut down on the number of configuration steps when generating the geodatabase, everything that could be changed in the model was modified.

Figure 2
Figure 2: Conceptual view of UNETRANS model

The Geodatabase Designer can export and import an XML design from an existing geodatabase. (Note: There is no way to generate a VISIO template from an existing geodatabase.) VDOT found this useful for replicating a few changes, such as topology rules or assigned spatial references, that could not be modeled in Visio. For improved readability, the Geodatabase Designer tool was used to export the Designer XML from a geodatabase first built on the Visio XML. This modified XML was used to create a new geodatabase structure.

The process flow was as follows:

  • Build the ArcSDE geodatabase with Visio XML.
  • Export the ArcSDE XML schema with Geodatabase Designer.
  • Replace the equivalent information in the Geodatabase Designer XML export with the target database specific information at the top of the Geodatabase Designer file. Be sure to make backup copies of all files, and do not apply this method to a loaded geodatabase.

Geodatabase Diagrammer

This tool was used to create a Visio presentation stub diagram from a geodatabase. Esri uses this to generate part of its object model diagrams and posters.

SDELoader Tool

VDOT used the SDELoader tool to calculate recommended spatial extents, precision, and grids used in configuring the spatial references for the feature datasets.

EditorID Tool

VDOT customized the ArcObjects EditorID tool to track the user name and time stamp of any edits to the features or table rows in the geodatabase. This required adding two new fields, EditorName and LastUpdate, to each table as a data model modification.

Some Caveats about Networks, Versioning, and Topology

No specific tools for managing the transportation-specific network or DOT-specific business requirements and reporting were included with the UNETRANS model, and using the editing tools in ArcMap can cause some problems. VDOT discovered that a topology and a network could not be applied to the same feature dataset at the same time. Network editing tools caused all related table information to be orphaned when an existing road segment was split. The split tool, when used with topology editing, did not break the link to related tables.

Figure 3
Figure 3: The network showing the connected points and lines feature classes

Topology editing did not automatically orphan the old links, and the existing links were cached in the attribute editor. To speed data loading, as recommended for initial loads, VDOT dropped the network and then rebuilt it using the Geodatabase Designer tool to export just the network or topology designs.

Every day, each user creates a version for all editing activity. At the end of the day, all edits are reconciled and posted, and the version is deleted. An ArcSDE batch process was put in place to automatically compress and analyze the geodatabase each night.

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