The World Geodetic System (WGS) is a standard for use in cartography, geodesy, and satellite navigation including GPS. This standard includes the definition of the coordinate system's fundamental and derived constants, the normal gravity Earth Gravitational Model (EGM), a description of the associated World Magnetic Model (WMM), and a current list of local datum transformations.
The latest revision is WGS 84 (also known as WGS 1984 ensemble):
- EPSG:4326 for 2D coordinate reference system (CRS),
- EPSG:4979 for 3D CRS
- EPSG:4978 for geocentric 3D CRS
It is established and maintained by the United States National Geospatial-Intelligence Agency since 1984, and last revised in January 2021 (G2139 frame realization). WGS 84 ensemble is static, while frame realisations have an epoch. Earlier schemes included WGS 72, WGS 66, and WGS 60. WGS 84 is the reference coordinate system used by the Global Positioning System.
As CRS standard, and expressing by URN, urn:ogc:def:crs:EPSG::4326, it is composed of:
- a standard reference ellipsoid model, named
urn:ogc:def:ellipsoid:EPSG::7030; - and this ellipsoid is located a standard horizontal datum, named
urn:ogc:def:datum:EPSG::6326.
Not all frame realisations (such as G1762’, 29 January 2017, GPS week 1934) are in EPSG under WGS 84, but under IGS14. G1762’ was the first time IGS14 was used.
On 27 November 2022 move to IGS20 is planned.
Work in progress...