PDA

Personal Digital Assistant, a portable computing device that can be carried into battle and used to receive or transmit information for the mapping application.

projection

A map projection is a mathematical transformation to project the surface of the Earth, or a portion of it, onto a flat surface such as a piece of paper or a computer screen. Since the Earth has an ellipsoidal shape, attempts to project its points on a plane always results in some kind of distortion of conformality, distance, direction, scale, and area. Map projections fall into three main categories: cylindrical, conic, or azimuthal. A projection can also be conformal, meaning that it preserves angles, or equal area, meaning that it displays true area ratio. A map has always an associated projection.

property

Characteristic of an object to which you can assign values.