A Geographic Coordinate System (GCS) is a system that uses a three-dimensional spherical surface to define locations on the Earth. It is primarily based on latitude and longitude, which are measured in degrees. Latitude indicates how far north or south a point is from the equator, while longitude indicates how far east or west a point is from the prime meridian. The GCS is essential for mapping and navigation, allowing for precise location identification. It is widely used in various fields, including cartography, geographic information systems (GIS), and navigation technologies, enabling users to understand and analyze spatial relationships on the Earth's surface.