EPSG:4978 — WGS 84
WGS 84 (geocentric) — the 3-D Cartesian Earth-Centred Earth-Fixed system used internally by GPS and most geodetic computations.
PROJ definition
+proj=geocent +datum=WGS84 +units=m +no_defs +type=crs
Geographic bounds
W -180° S -90° E 180° N 90°
Convert coordinates with EPSG:4978
Official EPSG transformations for WGS 84
Datum transformations involving EPSG:4978 published in the EPSG dataset, with parameters, accuracy and area of use:
About EPSG:4978
EPSG:4978 is the WGS 84 datum expressed as a geocentric Cartesian (XYZ) system: origin at Earth's centre of mass, X axis through 0°N 0°E, Z axis along the conventional International Reference Pole, Y axis right-handed. Coordinates are in metres.
Geocentric XYZ is the form GPS receivers actually use internally — every position is computed from satellite ranging in this frame and only converted to lat/lon (EPSG:4326) for display. It is also the natural CRS for satellite orbit work, geodynamics, and Helmert datum transformations: parameters are always expressed as a translation/rotation/scale between two geocentric frames.
For everyday GIS use, prefer EPSG:4326 or a projected CRS. Use EPSG:4978 when you need to apply a Helmert transformation, fit a tectonic-plate motion model, or interface with raw GNSS output.
Common use cases
- GPS receiver internals and satellite tracking
- Helmert seven-parameter datum transformations
- Geodetic computations on the WGS 84 ellipsoid
- Earth orientation and plate-motion modelling
Common transformations from EPSG:4978
- EPSG:4978 → EPSG:4326WGS 84 → WGS 84
- EPSG:4978 → EPSG:3857WGS 84 → WGS 84 / Pseudo-Mercator
- EPSG:4978 → EPSG:3395WGS 84 → WGS 84 / World Mercator
- EPSG:4978 → EPSG:7789WGS 84 → ITRF2014
- EPSG:4978 → EPSG:4267WGS 84 → NAD27
- EPSG:4978 → EPSG:4269WGS 84 → NAD83
- EPSG:4978 → EPSG:6318WGS 84 → NAD83(2011)
- EPSG:4978 → EPSG:4322WGS 84 → WGS 72
- EPSG:4978 → EPSG:26910WGS 84 → NAD83 / UTM zone 10N
- EPSG:4978 → EPSG:26911WGS 84 → NAD83 / UTM zone 11N
- EPSG:4978 → EPSG:26912WGS 84 → NAD83 / UTM zone 12N
- EPSG:4978 → EPSG:26913WGS 84 → NAD83 / UTM zone 13N
Frequently asked questions
- How do I convert WGS 84 lat/lon to ECEF XYZ?
- Use the geographic-to-geocentric formula on the WGS 84 ellipsoid (a = 6,378,137 m, 1/f = 298.257223563). proj4js does this automatically when you transform between EPSG:4326 and EPSG:4978.
- What's the difference between EPSG:4978 and EPSG:4979?
- EPSG:4978 is geocentric Cartesian (X, Y, Z in metres). EPSG:4979 is geographic 3-D (latitude, longitude, ellipsoidal height) on the same WGS 84 datum.
- What is the proj4 string for EPSG:4978?
- The proj4 definition for EPSG:4978 is: +proj=geocent +datum=WGS84 +units=m +no_defs +type=crs
- Where is EPSG:4978 used?
- EPSG:4978 (WGS 84) is defined for the area: World.