Using the Define Global Coordinate System command (ADEDEFCRDSYS) in AutoCAD Map 3D, you can define new coordinate systems or modify coordinate systems that you have previously defined. You cannot replace, rename, or modify the predefined coordinate systems that are provided with AutoCAD Map 3D; however, you can make a copy of a predefined coordinate system and modify the copy.
Coordinate system files are stored as shared files in the following location:
\Documents and Settings\All Users\Application Data\Autodesk\Geospatial Coordinate Systems
The main files are: coordsys.csd, datums.csd, elipsoid.csd, and category.csd. In addition, some datums may have an associated .mrt file. Defining or modifying a coordinate system modifies one or more of these coordinate system files.
When you install AutoCAD Map 3D, updated versions of these coordinate system files are installed. If you defined custom coordinate systems in a previous release of AutoCAD Map 3D, those custom coordinate systems are transferred automatically to the current coordinate system files when you install AutoCAD Map 3D.
However, if you continue to use an older version of AutoCAD Map 3D to define custom coordinate systems, you will need to manually add them to the new files. Use the Autodesk Coordinate System Update Utility to transfer custom coordinate system definitions from a previous release of AutoCAD Map 3D into the current AutoCAD Map 3D coordinate system files.
You cannot transfer custom coordinate systems from a newer version of the coordinate system files to an older version.
Note Do not use the CSUPDATE utility that shipped with previous versions of AutoCAD Map 3D to update the current AutoCAD Map 3D coordinate system files.