A geographic coordinate system uses which unit of measure?

A geographic coordinate system is designed to represent locations on the Earth's surface using a spherical or ellipsoidal model. This system employs angular measurements to define the position of points. Specifically, it uses latitude and longitude, where latitude represents the angle north or south of the equator, and longitude represents the angle east or west of the Prime Meridian. Because these measurements are based on angles, angular units such as degrees, minutes, and seconds are the appropriate choice for a geographic coordinate system.

In contrast, linear units are typically used in projected coordinate systems, which represent flat, two-dimensional surfaces rather than the curvature of the Earth. Planar measurement pertains to flat or two-dimensional spaces, while conical refers to a specific type of map projection rather than a unit of measure. Therefore, the use of angular measurement is key in understanding and utilizing geographic coordinate systems accurately.