To Check If a Coordinate System Has an EPSG Code

When you exchange data with ArcGIS, it is recommended to use a coordinate system that has an EPSG code.

If a drawing uses a coordinate system that does not have an EPSG code, there might be small x,y offset added to the data when it is saved back to ArcGIS if the data exists outside of the coordinate system's useful range.

You can use the MAPCSASSIGN command to check if a coordinate system has an EPSG code and to review a coordinate system's useful range.

Important: Before bringing ArcGIS data into a drawing with the Autodesk Connector for ArcGIS, install the ArcGIS Projection Engine Data. The Projection Engine Data prevents a coordinate offset from occurring when you bring ArcGIS data into a drawing. To prevent a coordinate offset issue from occurring when you save back to ArcGIS, you can use a coordinate system that has an EPSG code.

To check if a coordinate system has an EPSG code

1. At the command line, enter MAPCSASSIGN to display the Coordinate System dialog box.

   The currently assigned code is displayed at the top of the dialog box.

   Note: Some coordinate systems are not supported when publishing to ArcGIS or exporting to FGDB. For more information, see Coordinate Systems Not Supported When Exchanging Data with ArcGIS.
2. In the Search box, enter the code, such as NH83F.

   If the coordinate system has an EPSG code, it is displayed in the EPSG column.

   If the coordinate system does not have an EPSG code, you can check useful range of the coordinate system using the following procedure.

To check a coordinate system's useful range

If a coordinate system does not have an EPSG code, there might be small x,y offset added to ArcGIS data when it is saved back to ArcGIS if the data is created outside of the coordinate system's useful range.

1. Follow the steps in the procedure above.
2. Select the coordinate system in the Coordinate System dialog box.
3. Click View.
4. On the left pane of the window, click Parameters.
5. Review the Useful Range information.

Important: Even if a coordinate system has an EPSG code or the data is within the useful range of a coordinate system that does not have an EPSG code, you must install the ArcGIS Projection Engine Data to prevent a coordinate offset from occurring when bringing ArcGIS data into a drawing.