What is a datum in the context of GPS?

In the context of GPS, a datum refers to a coordinate system reference point used for defining the position of geographical locations on the Earth. Specifically, a datum encompasses a model of the Earth's shape and size, along with a starting point from which geographical measurements are made. Different datums can result in different location readings, as they can be based on varying mathematical models and reference frames.

Using a datum is essential for accurate positioning and mapping. GPS devices typically utilize specific datums to compute the precise coordinates of a user's location. The most common datums used in GPS are WGS84 (World Geodetic System 1984), which is the standard used by GPS systems, and several regional datums that may be relevant in specific geographical areas.

Understanding that a datum serves as a reference point and coordinate system clarifies how GPS technology translates satellite signals into usable location data.