Based on local mapping requirements, you can choose a projection and define the coordinate system you require by tailoring it to fit the needs of various mapping situations. The benefits of existing models are demonstrated as they relate to the earth as well as flat mapping representations.

The process of mapping a curved surface to produce a flat "map" involves defining a coordinate system:

• Choose a projection that minimizes distortion for the local mapping area.
• Datum/ellipsoid selection.
• Linear Unit selection.