What does a datum represent in navigation?

A datum in navigation serves as a mathematical model of the Earth, essential for performing calculations related to position, mapping, and navigation. It provides a reference framework that standardizes how geographic information is represented. This model accounts for the shape and size of the Earth, which is not a perfect sphere but an oblate spheroid, aiding in accurate coordination and positioning.

Using a datum allows navigators to relate the three-dimensional locations of points on the Earth's surface to two-dimensional representations on charts and maps. Different datums can distort distances, areas, and angles if used interchangeably without proper adjustments, which highlights their importance in ensuring precision in navigation and geographical analysis.

In contrast, while specific coordinates of a navigational point are vital, they rely on the underlying datum for accuracy. Changes in the Earth's atmosphere, although influential in navigation, do not define what a datum is, and charting a course involves additional processes that go beyond merely the concept of a datum.