Click the Map | Change Projection command or click the button to open the Assign Coordinate System dialog. The Assign Coordinate System dialog is used in new projects, before data is imported and in projects with existing projections when changing the projection.
If the Map | Change Projection command is not available, a coordinate system has not been defined for the current project. Click the Map | Coordinate Conversion command first. Set the coordinate system in the Coordinate Conversion dialog. This is the system the project uses for the current reference. After the coordinate system is set, click the Map | Change Projection command to change it to a new system.
Projecting Maps in Didger
Introduction to Map Projections
Geometric Forms of Projection
Characteristics of Projections
Latitude/Longitude in Decimal Degrees
Using Scaling to Minimize Distortion in Latitude/Longitude Projects