To Check If a Co-ordinate System Has an EPSG Code

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

If a drawing uses a co-ordinate 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 co-ordinate system's useful range.

You can use the MAPCSASSIGN command to check if a co-ordinate system has an EPSG code and to review a co-ordinate 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 co-ordinate offset from occurring when you bring ArcGIS data into a drawing. To prevent a co-ordinate offset issue from occurring when you save back to ArcGIS, you can use a co-ordinate system that has an EPSG code.

To check if a co-ordinate system has an EPSG code

1. At the command line, enter MAPCSASSIGN to display the Co-ordinate System dialog box.

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

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

   If the co-ordinate system has an EPSG code, it is displayed in the EPSG column.

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

To check a co-ordinate system's useful range

If a co-ordinate 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 co-ordinate system's useful range.

1. Follow the steps in the procedure above.
2. Select the co-ordinate system in the Co-ordinate 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 co-ordinate system has an EPSG code or the data is within the useful range of a co-ordinate system that does not have an EPSG code, you must install the ArcGIS Projection Engine Data to prevent a co-ordinate offset from occurring when bringing ArcGIS data into a drawing.