July - September 2004
Tract Editor GIS ApplicationThe SFWMD IRIS Tract Editor GIS application was developed using the ArcGIS 8.3 ArcMap interface modified using ArcObjects. The Tract Editor contains a task bar that enables the user to perform application functions as a step-by-step work flow process. Only tools relevant to the current task are enabled, and unrelated tools are temporarily disabled. This approach lets the application keep track of all edits the user performs throughout a session. At the end of an editing session, the GIS editor checks in the multiversioned edited personal geodatabase for the QA/QC manager, who approves and posts all the edits done back to an ArcSDE geodatabase. The process of posting the edits to ArcSDE utilizes the disconnected editing technology available from Esri.
IRIS GIS GeodatabaseThe SFWMD IRIS GIS Tract Editor application provides a toolset for maintaining the IRIS GIS data layers in a versioned, multiuser ArcSDE/Oracle geodatabase. The ArcSDE database is maintained on a server in the GIS Services section of the Information Technology Department which is located at the district in West Palm Beach, Florida.
Spatial data stored in the IRIS geodatabase consists of one feature dataset containing four related feature classes and one or more standalone feature classes. SFWMD_LANDS, the primary feature dataset in the geodatabase, serves as a container for logically related feature classes and tables. This feature dataset contains three feature classes-the TRACTS, EASEMENTS, and HISTORY layers.
The TRACTS layer is composed of tract polygons that indicate contiguous areas of ownership that were created by dissolving adjacent parcel boundaries with the same owner. Tracts are the geographic units of land management that underlay all district land acquisition activities. Tracts are lands owned by the district and its partners, land being considered for acquisition, or easements granted to the district.
The EASEMENTS layer, representing easements granted by the district over district-owned lands to other entities, is represented by polygons in the EASEMENTS layer within the SFWMD_LANDS feature dataset.
The HISTORY layer contains time-stamped copies of all edited tract polygons and a feature-linked annotation class. Whenever a tract polygon is edited, whether for merging, splitting, deleting, or modifying, the original polygon is copied to the HISTORY feature class. This allows the appearance of the tract layer to be reconstructed at any point in time based on the copy of the polygon and a time stamp.
Polygons in the history layer retain their original IDs, which are also recorded in the tract genealogy table. This table, combined with the series of changes to geometry stored in the history layer, allows users to reconstruct the chain of ownership in space as well as time. The feature-linked annotation is the district's tract number derived from the ACQ_ID field, a unique identifier used to track the acquisition business process.
Building the IRIS Geodatabase
To build the IRIS geodatabase, the Land Resources GIS section migrated coverages to ArcSDE/Oracle using ArcGIS 8.3. A major data validation effort identified inconsistencies between the two legacy databases. This was a monumental undertaking that included formulating SQL statements and writing ArcInfo ARC Macro Language (AML) scripts to identify many of these inconsistencies.
Resolving these inconsistencies required varying degrees of effort. In some cases, it was easy to identify which database held the correct information. In other cases, it took hours of research because many records hadn't been updated for decades. This process was repeated for each of the 25,000 records. Once the data validation was completed, the data was migrated into the versioned, multiuser ArcSDE/Oracle geodatabase at the district.
IRIS Tabular Database
The tabular data, stored in an Oracle database on a server hosted by Accela at the Qwest Communications Center in California, is served over the Internet with Accela Automation and Accela GIS. Macromedia ColdFusion and ArcIMS technology operating on a series of Web application servers provide this data using a Web browser. This information is currently available to all district offices, field stations, and service centers spread throughout the 16-county jurisdiction.
By the summer of 2004, the district will utilize XML technology to integrate the ArcSDE/Oracle geodatabase and the IRIS Oracle database between Florida and California. This integration effort will allow the GIS editors in the department to access and modify the IRIS Oracle database in California and the geodatabase in Florida simultaneously using the Tract Editor application communications module.
As a truly integrated enterprise system, IRIS has a solid foundation and the ability to evolve as new GIS, Web, and database systems emerge. It will aid efforts to restore America's Everglades for many years to come. For more information regarding restoring America's Everglades, visit www.evergladesplan.org. For information on the South Florida Water Management District, visit www.sfwmd.gov or e-mail Frank S. Razem at firstname.lastname@example.org.
About the Authors
Frank S. Razem is a specialist geographer associate who works for the South Florida Water Management District and has been involved in GIS for more than 10 years. Michael Rose is a project manager with GeoAnalytics, Inc. He has more than 15 years of GIS experience.