Surveying GIS-What's new in ArcGIS 9.2?
GIS is being used more and more as a framework for business management because it is often the best platform for integrating the various spatial and non-spatial data sets utilized by organizations large and small. Thus, the demand for a “global network” is a reality. And from here on, surveyors are going to be part of that global network, one way or another.
ESRI (Redlands, Calif.), which now has more than a million users worldwide, has recognized this growing demand for a global network with the release of ArcGIS version 9.2. ESRI has termed 9.2 a “significant release,” and also describes it as a paradigm shift because the bulk of the changes affect the server side of online map publishing and data distribution.
The GeodatabaseThis might be the most profound change in the approach to data we have seen from ESRI since the introduction of the original geodatabase in ArcGIS version 8.0. With ArcGIS 9.2, ESRI states it is “making some major improvements and enhancements to the data management capabilities of the software” and with good reason. (For a refresher on geodatabases, see “Surveying GIS: What is a geodatabase?” POB April 2003.)
Many users didn’t warm up to the MS Access-based Personal Geodatabase introduced in ArcGIS 8.0. Its most obvious limitation was the absence of multiple user editing capabilities. The 2 Gb threshold of its MS Access core was another. And the ArcSDE (Spatial Database Engine) option for multiple editors/users had some hefty hardware requirements and a steep learning curve. The new geodatabases are file-based and work with a variety of platforms. IBM DB2, IBM Informix, Microsoft SQL Server and Oracle are all supported. The earlier MS Access versions will be supported, but the product notes for this new release contain this statement: “Users will be encouraged to adopt file-based geodatabases as the native format for ArcGIS 9.2 and beyond.”
So, what does file-based mean? The standard geodatabase in its previous incarnation was built on a DBMS (Database Management System) such as the Microsoft Access .mdb platform. The new geodatabases are built on top of a file system. In construction, these are logically much like the good old-fashioned Shape file (.SHP). But these new geodatabases far outperform the Shape file in their capabilities. In a way, though, I suppose you could say it’s back to the future.
Before ArcGIS 9.2, a geodatabase could only be edited by multiple users if it had been “versioned.” Versioning has a very precise meaning in ArcGIS. It is a process that creates a special model for the data with certain characteristics. ArcGIS 9.2 has what is called a short-transaction editing model. The short-transaction editing model enables multi-user editing without the complexities of registering a version.
The new geodatabase comes in different strengths. Which geodatabase the user can adopt depends on which flavor of ArcGIS he has. Let’s review that licensing model again. ArcGIS is a suite of programs that includes ArcMap, ArcCatalog and ArcToolbox. But there are also three separate levels of ArcGIS licensed by ESRI: ArcGIS ArcView, ArcGIS ArcEditor and ArcGIS ArcINFO. ArcEditor is more robust than ArcView, and ArcINFO is the top of the product line. To utilize some of the advanced features of the new geodatabases, ArcEditor or ArcINFO is required.
The new geodatabase for workgroups has a 4 Gb capacity and is a Windows-only product. The Enterprise SDE for Workgroups is unlimited and supports Windows or Solaris.
Archiving CapabilityThe new archiving feature for geodatabases is something those of us who work in land bases and datum epochs have desired for a long time. It has been a long-held view that one of the great weaknesses of a typical geographic information system is that it lacks genealogy. In other words, only the most current data set is available for querying and mapping. When an edit is performed, the previous data is simply overwritten and lost. GIS users often resort to aerial imagery of different vintages for comparisons over time, but this method is limited to viewing the picture. Now, data set archiving allows the user to not only view earlier instances of a data set, but also query the earlier state of the data associated with it.
Intelligent CartographySome of the new features in 9.2 are described as Intelligent Cartography tools. These include a new .pdf (Portable Document File) writer that allows layer control in the .pdf. A whole new set of COGO tools make it a little more surveyor-friendly and a new built-in conflict resolution feature overrides symbology issues. Those resolutions only affect the layout or plot version.
ArcGIS 9.2 follows the usual ESRI business practice of incorporating functions that formerly were only available in plug-ins and extensions. The ECW reader, for instance, which allows direct access to ER Mapper’s compressed wavelet (EC format), comes pre-loaded on version 9.2. But watch out: if you have these plug-ins installed in existing versions, you need to uninstall them along with version 9.0 or 9.1
CADD EnhancementsThe first feature concomitant CADD/GIS users will notice in version 9.2 is the improved scroll mouse functionality. This handy feature has been around in CADD products for several years. Just as it does in CADD, this feature allows the user to move quickly and easily anywhere in the map view.
Better yet is the improved symbology for CADD files. More of the layer properties of the original drawing file are retained in 9.2 and the file appears much more as it did in the CADD environment. Colors, fills and line symbols are more closely matched to their original CADD appearances.
In addition to the CADD enhancements, 9.2 offers direct reading of another commonly used file type--Microsoft Excel files. The user can view the contents of Excel files in ArcCatalog or bring them directly into the map view and right-click on the file in the table of contents.
Microsoft Excel tables such as the one on page 45 that contain X-Y values can easily be converted to layers for viewing in the map view. If the Excel table has an “Object ID” field, it can be added to the map using the “Add X-Y Data” button in the tools menu.
If the user needs help with the Spatial Database Engine (SDE), the new help files are much more task-oriented than in the previous releases.
Additional InformationThere are, of course, many more changes and improvements in ArcGIS 9.2 than we can cover here. ESRI usually provides additional support for new releases and significant upgrades to their products. ArcGIS 9.2 is no exception. There is a free online course titled “What’s New in the Geodatabase at Arc 9.2” available on the Virtual Campus portal on ESRI’s website at http://train ing.esri.com/acb2000/showdetl.cfm?DID=6&Product_ID=864 (also available in Spanish).
Note: ESRI uses the generic term “Windows” with respect to product support. Windows XP was the predominant operating system at the time the release notes were issued. As of this writing, it is not known what the impact of Microsoft’s new Vista operating system will have on these products.