- In ArcCatalog, click the shapefile whose coordinate system you want to define.
- Click the File menu and click Properties.
- Click the XY Coordinate System tab.
- Click Save As on the Shapefile Properties dialog box.
- Navigate to the location where you want to place the coordinate system file.
For example, place it in a shared folder on the network.
- Type a name for the coordinate system file and click Save.
- Click OK.
The coordinate system file appears in the folder's Contents list.