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ArcGIS 9.2 Notes

General

Unlike the previous versions, ArcGIS 9.2 stores the coordinates in double precision numbers. The geodatabases created in ArcGIS 9.2 are capable of storing double precision data and (although not an ESRI term) we will call them "High" precision geodatabases. The geodatabases created in the pre 9.2 versions of ArcGIS use single precision numbers and we will refer to them as "Low" precision databases. ArcGIS 9.2 introduces a new single-user geodatabase referred to as File geodatabase. The file geodatabases are "High" precision geodatabases.

Converting data from "Low" to "High" precision

The process involves two steps:

• Upgrading the geodatabase
  • In ArcCatalog right click on a geodatabase ==>Properties
  • In the Database Properties dialog click the Upgrade Geodatabase button
• Upgrading the spatial reference of the feature classes - use ArcToolbox ==> Data Management Tools ==> Database ==> Upgrade Spatial Reference tool

ArcGIS 9.2 and "Low" precision data

You cannot create "Low" (pre- 9.2) geodatabase with ArcGIS 9.2. If you want to create "Low" precision feature classes in ArcGIS 9.2 you need to have a template geodatabase created in an older ArcGIS version. In general:

• If you create a feature class in a "High" precision geodatabase it will be "High" precision
• If you create a feature class in a "Low" precision geodatabase it will be "Low" precision.

ET GeoWizards inputs and outputs.

The functions of ET GeoWizards can use as inputs datasets stored in both "High" and "Low" precision geodatabases and create outputs in both "High" and "Low" precision geodatabases. All the functions establish the type of the Input and the location of the output and make the necessary conversions.

Many of the functions are complex and need to create intermediate feature classes. Normally these feature classes are stored in a temporary geodatabase created by the software in the user defined temporary folder - see ET GeoWizards and geodatabases topic.

Since ArcGIS 9.2 cannot create pre-9.2 ("Low" precision) geodatabases, the installation of the software contains a template "Low" precision geodatabase. This database is called "et_tempGDB_pre92.mdb". It is copied automatically to the temp folder set by the user. This database is used to store intermediate "Low" precision data if the user selects as an output a "Low" precision database.