Target Coordinate System Properties
Maps can be displayed in any coordinate system. The map is displayed in the coordinate system defined as the Target Coordinate System. When a map layer uses a different Source Coordinate System than the map's Target Coordinate System, the map layer is converted to the map's Target Coordinate System.
3D surface layers and wireframe layers do not have a coordinate system associated with them and cannot be converted to a different coordinate system. For this reason, there is not a Coordinate System tab in the Properties window for the surface layer, the wireframe layer, the Map object, or any other map layer when either a surface layer or wireframe layer exists in the Map.
When a surface map or wireframe map is created, the Map object and Surface layer or the Map object and Wireframe layer are set to an unreferenced coordinate system. Any map layers subsequently added to the Map must be in the same units as the surface layer.
When a surface layer or wireframe layer is added to an existing map, the coordinate system of the existing map must first be set to the same coordinate system as the surface or wireframe map to be added. To determine the coordinate system for the surface or wireframe layer, you may need to create a contour map from the grid file, first. Match the Map coordinate system to this grid file. Then, add the surface map or wireframe map.
Coordinate System Page
The Coordinate System page is located in the Properties window when a Map object is selected.
Specify the map coordinate system on the Coordinate System page.
Click the Change button next to Coordinate system to open the Assign Coordinate System dialog. This dialog lets you set the desired target coordinate system. This is the coordinate system in which you want the map to be displayed.
Assign to Unreferenced Layers
Click the Assign Now button in the Assign to unreferenced layers field to apply the map target coordinate system to the source coordinate system for all map layers with an unreferenced coordinate system. The Assign to unreferenced layers operation only changes the source coordinate system for current map layers. If more map layers are added with unreferenced coordinate systems, then the Assign Now button must be clicked again to apply the target coordinate system to the new map layers.
Map Coordinate System Overview
Introduction to Common Map Properties
Assign Coordinate System Dialog
Introduction to Map Projections