The World Geodetic System 1984 (WGS-84 or WGS 1984) is a standard for use in cartography, geodesy, and navigation. It comprises a standard coordinate frame for the Earth, a standard spheroidal reference surface (the datum or reference ellipsoid) for raw altitude data, and a gravitational equipotential surface (the geoid) that defines the nominal sea level.
The WGS-84 provides a single, common, accessible 3-dimensional coordinate system for geospatial data collected from a broad spectrum of sources. Some of this geospatial data exhibits a high degree of metric fidelity and requires a global reference frame which is free of any significant distortions or biases. For this reason, a series of improvements to WGS-84 have been developed, which served to refine the original version.