# World Geodetic System

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Geodetic reference system

Geodesy Fundamentals Geodesy Geodynamics Geomatics History Concepts Geographical distance Geoid Figure of the Earth (radius and circumference) Geodetic coordinates Geodetic datum Geodesic Horizontal position representation Latitude / Longitude Map projection Reference ellipsoid Satellite geodesy Spatial reference system Spatial relations Vertical positions Technologies Global Nav. Sat. Systems (GNSSs) Global Pos. System (GPS) GLONASS (Russia) BeiDou (BDS) (China) Galileo (Europe) NAVIC (India) Quasi-Zenith Sat. Sys. (QZSS) (Japan) Discrete Global Grid and Geocoding Standards (history) NGVD 29 Sea Level Datum 1929 OSGB36 Ordnance Survey Great Britain 1936 SK-42 Systema Koordinat 1942 goda ED50 European Datum 1950 SAD69 South American Datum 1969 GRS 80 Geodetic Reference System 1980 ISO 6709 Geographic point coord. 1983 NAD 83 North American Datum 1983 WGS 84 World Geodetic System 1984 NAVD 88 N. American Vertical Datum 1988 ETRS89 European Terrestrial Ref. Sys. 1989 GCJ-02 Chinese obfuscated datum 2002 Geo URI Internet link to a point 2010 International Terrestrial Reference System Spatial Reference System Identifier (SRID) Universal Transverse Mercator (UTM) v t e

The **World Geodetic System** (**WGS**) is a standard used in [cartography](/source/Cartography), [geodesy](/source/Geodesy), and [satellite navigation](/source/Satellite_navigation) including [GPS](/source/GPS). The current version, **WGS 84**, defines an [Earth-centered, Earth-fixed coordinate system](/source/Earth-centered%2C_Earth-fixed_coordinate_system) and a [geodetic datum](/source/Geodetic_datum), and also describes the associated [Earth Gravitational Model](/source/Earth_Gravitational_Model) (EGM) and [World Magnetic Model](/source/World_Magnetic_Model) (WMM). The standard is published and maintained by the United States [National Geospatial-Intelligence Agency](/source/National_Geospatial-Intelligence_Agency).[1]

## History

Efforts to supplement the various national [surveying](/source/Surveying) systems began in the 19th century with [F.R. Helmert's](/source/Friedrich_Robert_Helmert) book *Mathematische und Physikalische Theorien der Physikalischen Geodäsie* (*Mathematical and Physical Theories of Physical Geodesy*). [Austria](/source/Austria) and [Germany](/source/Germany) founded the *Zentralbüro für die Internationale Erdmessung* (Central Bureau of International [Geodesy](/source/Geodesy)), and a series of global [ellipsoids](/source/Ellipsoid) of the Earth were derived (e.g., Helmert 1906, [Hayford](/source/John_Fillmore_Hayford) 1910 and 1924).

A unified geodetic system for the whole world became essential in the 1950s for several reasons:

- International [space science](/source/Space_science) and the beginning of [astronautics](/source/Astronautics).

- The lack of inter-continental geodetic information.

- The inability of the large [geodetic systems](/source/Geodetic_system), such as European Datum ([ED50](/source/ED50)), [North American Datum](/source/North_American_Datum) (NAD), and [Tokyo](/source/Tokyo) Datum (TD), to provide a worldwide geo-data basis

- Need for global maps for [navigation](/source/Navigation), aviation, and [geography](/source/Geography).

- Western [Cold War](/source/Cold_War) preparedness necessitated a standardised, [NATO](/source/NATO)-wide geospatial reference system, in accordance with the NATO [Standardisation Agreement](/source/STANAG)

### WGS 60

In the late 1950s, the [United States Department of Defense](/source/United_States_Department_of_Defense), together with [scientists](/source/Scientist) of other institutions and countries, began to develop the needed world system to which geodetic data could be referred and compatibility established between the coordinates of widely separated sites of interest. Efforts of the U.S. Army, Navy and Air Force were combined leading to the DoD World Geodetic System 1960 (WGS 60). The term *datum* as used here refers to a smooth surface somewhat arbitrarily defined as zero elevation, consistent with a set of surveyor's measures of distances between various stations, and differences in elevation, all reduced to a grid of [latitudes](/source/Latitude), [longitudes](/source/Longitude), and [elevations](/source/Elevation). Heritage surveying methods found elevation differences from a local horizontal determined by the [spirit level](/source/Spirit_level), [plumb line](/source/Plumb-bob), or an equivalent device that depends on the local gravity field (see [physical geodesy](/source/Physical_geodesy)). As a result, the elevations in the data are referenced to the [geoid](/source/Geoid), a surface that is not readily found using [satellite geodesy](/source/Satellite_geodesy). The latter observational method is more suitable for global mapping. Therefore, a motivation, and a substantial problem in the WGS and similar work is to patch together data that were not only made separately, for different regions, but to re-reference the elevations to an ellipsoid model rather than to the [geoid](/source/Geoid).

Gravimetric datum orientation.
  Ellipsoid of [astro-geodetically](/source/Geodetic_astronomy) oriented datum

  [Geoid](/source/Geoid)

  [Gravimetrically](/source/Gravimetry)-oriented ellipsoid

In accomplishing WGS 60, a combination of available surface [gravity](/source/Gravity) data, [astro-geodetic](/source/Astro-geodetic) data and results from HIRAN[2] and Canadian [SHORAN](/source/SHORAN) surveys were used to define a best-fitting [ellipsoid](/source/Ellipsoid) and an earth-centered orientation for each initially selected datum. (Every datum is relatively oriented with respect to different portions of the geoid by the astro-geodetic methods already described.) The sole contribution of [satellite](/source/Satellite) data to the development of WGS 60 was a value for the [ellipsoid](/source/Ellipsoid) flattening which was obtained from the nodal motion of a satellite.

Prior to WGS 60, the U.S. Army and [U.S. Air Force](/source/U.S._Air_Force) had each developed a world system by using different approaches to the gravimetric datum orientation method. To determine their gravimetric orientation parameters, the Air Force used the mean of the differences between the gravimetric and astro-geodetic [deflections](/source/Vertical_deflection) and geoid heights (undulations) at specifically selected stations in the areas of the major datums. The Army performed an adjustment to minimize the difference between astro-geodetic and [gravimetric](/source/Gravimetric) [geoids](/source/Geoid). By matching the relative astro-geodetic geoids of the selected datums with an earth-centered gravimetric geoid, the selected datums were reduced to an earth-centered orientation. Since the Army and Air Force systems agreed remarkably well for the NAD, ED and TD areas, they were consolidated and became WGS 60.

### WGS 66

Improvements to the global system included the Astrogeoid of [Irene Fischer](/source/Irene_Fischer) and the astronautic Mercury datum. In January 1966, a World Geodetic System Committee composed of representatives from the United States Army, Navy and Air Force was charged with developing an improved WGS, needed to satisfy [mapping](/source/Map), charting and geodetic requirements. Additional surface [gravity](/source/Gravity) observations, results from the extension of [triangulation](/source/Triangulation) and [trilateration](/source/Trilateration) networks, and large amounts of [Doppler](/source/Doppler_radar) and [optical](/source/Optical) satellite data had become available since the development of WGS 60. Using the additional data and improved techniques, WGS 66 was produced which served DoD needs for about five years after its implementation in 1967. The defining parameters of the WGS 66 Ellipsoid were the flattening (1⁄298.25 determined from satellite data) and the semimajor axis (6378145 m determined from a combination of Doppler satellite and astro-geodetic data). A worldwide 5° × 5° mean free air [gravity anomaly](/source/Gravity_anomaly) field provided the basic data for producing the WGS 66 gravimetric geoid. Also, a geoid referenced to the WGS 66 Ellipsoid was derived from available astrogeodetic data to provide a detailed representation of limited land areas.

### WGS 72

After an extensive effort over a period of approximately three years, the Department of Defense World Geodetic System 1972 was completed. Selected satellite, surface gravity and astrogeodetic data available through 1972 from both DoD and non-DoD sources were used in a Unified WGS Solution (a large scale [least squares](/source/Least_squares) adjustment). The results of the adjustment consisted of corrections to initial station coordinates and coefficients of the gravitational field.[3]

The largest collection of data ever used for WGS purposes was assembled, processed and applied in the development of WGS 72. Both optical and electronic satellite data were used. The electronic satellite data consisted, in part, of Doppler data provided by the U.S. Navy and cooperating non-DoD satellite tracking stations established in support of the Navy's Navigational Satellite System (NNSS). Doppler data was also available from the numerous sites established by GEOCEIVERS during 1971 and 1972. Doppler data was the primary data source for WGS 72 (see image). Additional electronic satellite data was provided by the SECOR (Sequential Collation of Range) Equatorial Network completed by the U.S. Army in 1970. Optical satellite data from the Worldwide Geometric Satellite Triangulation Program was provided by the BC-4 camera system (see image). Data from the [Smithsonian Astrophysical Observatory](/source/Smithsonian_Astrophysical_Observatory) was also used which included camera ([Baker–Nunn](/source/Schmidt_camera#Baker–Nunn)) and some laser ranging.[3]

Doppler satellite ground stations providing data for WGS 72 development

Worldwide geometric satellite triangulation network, BC-4 cameras

The surface gravity field used in the Unified WGS Solution consisted of a set of 410 10° × 10° equal area mean free air gravity anomalies determined solely from terrestrial data. This gravity field includes mean anomaly values compiled directly from observed gravity data wherever the latter was available in sufficient quantity. The value for areas of sparse or no observational data were developed from geophysically compatible gravity approximations using gravity-geophysical correlation techniques. Approximately 45 percent of the 410 mean free air gravity anomaly values were determined directly from observed gravity data.[3]

The astrogeodetic data in its basic form consists of deflection of the vertical components referred to the various national geodetic datums. These deflection values were integrated into astrogeodetic geoid charts referred to these national datums. The geoid heights contributed to the Unified WGS Solution by providing additional and more detailed data for land areas. Conventional ground survey data was included in the solution to enforce a consistent adjustment of the coordinates of neighboring observation sites of the BC-4, SECOR, Doppler and Baker–Nunn systems. Also, eight [geodimeter](/source/Geodimeter) long line precise traverses were included for the purpose of controlling the scale of the solution.[3]

The Unified WGS Solution, as stated above, was a solution for geodetic positions and associated parameters of the gravitational field based on an optimum combination of available data. The WGS 72 ellipsoid parameters, datum shifts and other associated constants were derived separately. For the unified solution, a normal equation matrix was formed based on each of the mentioned data sets. Then, the individual normal equation matrices were combined and the resultant matrix solved to obtain the positions and the parameters.[3]

The value for the semimajor axis (a) of the WGS 72 Ellipsoid is 6378135 m. The adoption of an a-value 10 meters smaller than that for the WGS 66 Ellipsoid was based on several calculations and indicators including a combination of satellite and surface gravity data for position and gravitational field determinations. Sets of satellite derived station coordinates and gravimetric deflection of the vertical and geoid height data were used to determine local-to-geocentric datum shifts, datum rotation parameters, a datum scale parameter and a value for the semimajor axis of the WGS Ellipsoid. Eight solutions were made with the various sets of input data, both from an investigative point of view and also because of the limited number of unknowns which could be solved for in any individual solution due to computer limitations. Selected Doppler satellite tracking and astro-geodetic datum orientation stations were included in the various solutions. Based on these results and other related studies accomplished by the committee, an a-value of 6378135 m and a flattening of 1/298.26 were adopted.[3]

In the development of local-to WGS 72 datum shifts, results from different geodetic disciplines were investigated, analyzed and compared. Those shifts adopted were based primarily on a large number of Doppler TRANET and GEOCEIVER station coordinates which were available worldwide. These coordinates had been determined using the Doppler point positioning method.[3]

### WGS 84

Equatorial (a), polar (b) and mean Earth radii as defined in the 1984 World Geodetic System revision (not to scale)

In the early 1980s, the need for a new world geodetic system was generally recognized by the geodetic community as well as within the US Department of Defense. WGS 72 no longer provided sufficient data, information, geographic coverage, or product accuracy for all then-current and anticipated applications. The means for producing a new WGS were available in the form of improved data, increased data coverage, new data types and improved techniques. Observations from Doppler, satellite laser ranging and [very-long-baseline interferometry](/source/Very-long-baseline_interferometry) (VLBI) constituted significant new information. An outstanding new source of data had become available from satellite radar altimetry. Also available was an advanced [least squares](/source/Least_squares) method called [collocation](/source/Collocation_method) that allowed for a consistent combination solution from different types of measurements all relative to the Earth's gravity field, measurements such as the geoid, gravity anomalies, deflections, and dynamic Doppler.

The new world geodetic system was called WGS 84. It is the reference system used by the [Global Positioning System](/source/Global_Positioning_System). It is geocentric and globally consistent within 1 [m](/source/Metre). Current geodetic realizations of the geocentric reference system family [International Terrestrial Reference System](/source/International_Terrestrial_Reference_System) (ITRS) maintained by the [IERS](/source/IERS) are geocentric, and internally consistent, at the few-cm level, while still being metre-level consistent with WGS 84.

The WGS 84 [reference ellipsoid](/source/Reference_ellipsoid) was based on [GRS 80](/source/GRS_80), but it contains a very slight variation in the inverse flattening, as it was derived independently and the result was rounded to a different number of significant digits.[4] This resulted in a tiny difference of 0.105 mm in the semi-minor axis.[5] The following table compares the primary ellipsoid parameters.

Ellipsoid reference Semi-major axis a Semi-minor axis b Inverse flattening 1⁄f GRS 80 6378137.0 m ≈ 6356752.314140 m 298.257222100882711... WGS 84[6] 6378137.0 m ≈ 6356752.314245 m 298.257223563

## Definition

WGS 84 reference frame. The oblateness of the ellipsoid is exaggerated in this image.

The coordinate origin of WGS 84 is meant to be located at the Earth's [center of mass](/source/Center_of_mass); the uncertainty is believed to be less than 2 cm.[7]

Handheld GPS receiver at the [Royal Observatory, Greenwich](/source/Royal_Observatory%2C_Greenwich), indicating that the [Greenwich meridian](/source/Prime_meridian_(Greenwich)) is 0.089 [arcminutes](/source/Arcminute) (or 5.34 [arcseconds](/source/Arcsecond)) west of the WGS 84 datum (the [IERS Reference Meridian](/source/IERS_Reference_Meridian))

The WGS 84 meridian of zero longitude is the [IERS Reference Meridian](/source/IERS_Reference_Meridian),[8] 5.3 [arc seconds](/source/Minute_of_arc) or 102 metres (335 ft) east of the [Greenwich meridian](/source/Greenwich_meridian) at the latitude of the [Royal Observatory](/source/Royal_Observatory%2C_Greenwich).[9][10] (This is related to the fact that the [perpendicular to the local equipotential surface of the gravity field](/source/Vertical_deflection) at Greenwich does not point exactly through the Earth's center of mass, but rather "misses west" of the center of mass by about 102 meters.) The longitude positions on WGS 84 agree with those on the older [North American Datum 1927](/source/North_American_Datum) at roughly [85° longitude west](/source/85th_meridian_west), in the east-central United States.

The WGS 84 datum surface is an [oblate spheroid](/source/Oblate_spheroid) with equatorial radius a = 6378137 m at the [equator](/source/Equator) and [flattening](/source/Flattening) f = 1⁄298.257223563. The refined value of the WGS 84 [gravitational constant](/source/Standard_gravitational_parameter) (mass of Earth's atmosphere included) is GM = 3.986004418×1014 m3/s2. The angular velocity of the Earth is defined to be ω = 72.92115×10−6 rad/s.[11]

This leads to several computed parameters such as the polar semi-minor axis b which equals *a* × (1 − *f*) = 6356752.3142 m, and the first eccentricity squared, *e*2 = 6.69437999014×10−3.[11]

## Updates and new standards

The original standardization document for WGS 84 was Technical Report 8350.2, published in September 1987 by the Defense Mapping Agency (which later became the National Imagery and Mapping Agency). New editions were published in September 1991 and July 1997; the latter edition was amended twice, in January 2000 and June 2004.[12] The standardization document was revised again and published in July 2014 by the [National Geospatial-Intelligence Agency](/source/National_Geospatial-Intelligence_Agency) as NGA.STND.0036.[13] These updates provide refined descriptions of the Earth and realizations of the system for higher precision.

The original WGS84 model had an absolute accuracy of 1–2 meters. WGS84 (G730) first incorporated GPS observations, taking the accuracy down to 10 cm/component rms.[14] All following revisions including WGS84 (G873) and WGS84 (G1150) also used GPS.[15]

WGS 84 (G1762) is the sixth update to the WGS reference frame.[14]

WGS 84 has most recently been updated to use the reference frame **G2296**, which was released on 7 January 2024 as an update to G2139, now aligned to both the ITRF2020, the most recent ITRF realization, and the IGS20, the frame used by the International GNSS Service (IGS).[16] G2139 was aligned with the IGb14 realization of the [International Terrestrial Reference Frame](/source/International_Terrestrial_Reference_Frame) (ITRF) 2014 and uses the new [IGS](/source/International_GNSS_Service) Antex standard.[17]

Updates to the original [geoid](/source/Geoid) for WGS 84 are now published as a separate [Earth Gravitational Model](/source/Earth_Gravitational_Model) (EGM), with improved resolution and accuracy. Likewise, the [World Magnetic Model](/source/World_Magnetic_Model) (WMM) is updated separately. The current version of WGS 84 uses EGM2008 and WMM2025.[18][19]

Solution for Earth orientation parameters consistent with ITRF2014 is also needed (IERS EOP 14C04).[20]

## Identifiers

Components of WGS 84 are identified by codes in the [EPSG Geodetic Parameter Dataset](/source/EPSG_Geodetic_Parameter_Dataset):[21]

- EPSG:4326 – 2D [coordinate reference system](/source/Coordinate_reference_system) (CRS)

- EPSG:4979 – 3D CRS

- EPSG:4978 – [geocentric](/source/Earth-centered%2C_Earth-fixed_coordinate_system) 3D CRS

- EPSG:7030 – [reference ellipsoid](/source/Reference_ellipsoid)

- EPSG:6326 – [horizontal datum](/source/Geodetic_datum#Horizontal_datum)

## See also

- [Earth portal](https://en.wikipedia.org/wiki/Portal:Earth)
- [Earth Sciences portal](https://en.wikipedia.org/wiki/Portal:Earth_Sciences)
- [Geodesy portal](https://en.wikipedia.org/wiki/Portal:Geodesy)
- [History of Science portal](https://en.wikipedia.org/wiki/Portal:History_of_Science)

- [Degree Confluence Project](/source/Degree_Confluence_Project)

- [Earth Gravitational Model](/source/Earth_Gravitational_Model)

- [European Terrestrial Reference System 1989](/source/European_Terrestrial_Reference_System_1989)

- [Geo (microformat)](/source/Geo_(microformat)) – for marking up WGS 84 coordinates in (X)HTML

- [geo URI scheme](/source/Geo_URI_scheme)

- [Geographic information system](/source/Geographic_information_system)

- [Geotagging](/source/Geotagging)

- [GIS file format](/source/GIS_file_format)

- [North American Datum](/source/North_American_Datum)

- [Point of interest](/source/Point_of_interest)

- [Timeline of Earth estimates](/source/Timeline_of_Earth_estimates)

- [TRANSIT system](/source/Transit_(satellite))

## References

1. **[^](#cite_ref-homepage_1-0)** ["World Geodetic System 1984 (WGS 84)"](https://earth-info.nga.mil/?dir=wgs84&action=wgs84). *Office of Geomatics, National Geospatial-Intelligence Agency*. Retrieved 21 December 2022.

1. **[^](#cite_ref-2)** ["NOAA History - Stories and Tales of the Coast & Geodetic Survey - Personal Tales/Earth Measurer/Aslakson Bio"](http://www.history.noaa.gov/stories_tales/ak7.html). *History.noaa.gov*. Retrieved 24 May 2017.

1. ^ [***a***](#cite_ref-:0_3-0) [***b***](#cite_ref-:0_3-1) [***c***](#cite_ref-:0_3-2) [***d***](#cite_ref-:0_3-3) [***e***](#cite_ref-:0_3-4) [***f***](#cite_ref-:0_3-5) [***g***](#cite_ref-:0_3-6) ["THE WORLD GEODETIC SYSTEM"](https://www.ngs.noaa.gov/PUBS_LIB/Geodesy4Layman/TR80003E.HTM#ZZ11). [*Geodesy for the Layman*](https://www.ngs.noaa.gov/PUBS_LIB/Geodesy4Layman/toc.htm). United States Air Force. 1984.

1. **[^](#cite_ref-4)** Hooijberg, Maarten (18 December 2007). *Geometrical Geodesy: Using Information and Computer Technology*. Germany: Springer Berlin Heidelberg. p. 20. [ISBN](/source/ISBN_(identifier)) [9783540682257](https://en.wikipedia.org/wiki/Special:BookSources/9783540682257).

1. **[^](#cite_ref-5)** ["USER DOCUMENTATION Programs: INVERSE, FORWARD, INVERS3D, FORWRD3D Versions 2.0"](https://geodesy.noaa.gov/PC_PROD/Inv_Fwd/readme.htm). *geodesy.noaa.gov*. Retrieved 23 May 2022.

1. **[^](#cite_ref-6)** ["WGS 84: Ellipsoid Details"](https://epsg.org/ellipsoid_7030/WGS-84.html). *EPSG Geodetic Parameter Dataset*. Retrieved 21 December 2022.

1. **[^](#cite_ref-7)** ["The EGM96 Geoid Undulation with Respect to the WGS84 Ellipsoid"](https://cddis.nasa.gov/926/egm96/doc/S11.HTML). [NASA](/source/NASA).

1. **[^](#cite_ref-Manual_8-0)** [European Organisation for the Safety of Air Navigation](/source/EUROCONTROL) and [IfEN](https://en.wikipedia.org/w/index.php?title=Institute_of_Geodesy_and_Navigation&action=edit&redlink=1): WGS 84 Implementation Manual, p. 13. 1998

1. **[^](#cite_ref-9)** ["Greenwich Meridan, Tracing its History"](http://gpsinformation.net/main/greenwich.htm). *Gpsinformation.net*. Retrieved 24 May 2017.

1. **[^](#cite_ref-Malys_et_al._2015_10-0)** Malys, Stephen; Seago, John H.; Palvis, Nikolaos K.; Seidelmann, P. Kenneth; Kaplan, George H. (1 August 2015). ["Why the Greenwich meridian moved"](https://doi.org/10.1007%2Fs00190-015-0844-y). *Journal of Geodesy*. **89** (12): 1263–1272. [Bibcode](/source/Bibcode_(identifier)):[2015JGeod..89.1263M](https://ui.adsabs.harvard.edu/abs/2015JGeod..89.1263M). [doi](/source/Doi_(identifier)):[10.1007/s00190-015-0844-y](https://doi.org/10.1007%2Fs00190-015-0844-y).

1. ^ [***a***](#cite_ref-Second_Edition_11-0) [***b***](#cite_ref-Second_Edition_11-1) ["Department of Defense World Geodetic System 1984"](https://apps.dtic.mil/sti/pdfs/ADA280358.pdf) (PDF) (2nd ed.). Defense Mapping Agency. 1 September 1991. [Archived](https://web.archive.org/web/20210803171602/https://apps.dtic.mil/sti/pdfs/ADA280358.pdf) (PDF) from the original on 3 August 2021.

1. **[^](#cite_ref-12)** ["DMA TR 8350.2 WGS"](https://global.ihs.com/doc_detail.cfm?&item_s_key=00135849#doc-detail-history-anchor). *IHS Markit Standards Store*. Retrieved 26 December 2022.

1. **[^](#cite_ref-13)** ["Data collection of WGS 84 information — or is it?"](https://www.gpsworld.com/data-collection-of-wgs-84-information-or-is-it/). *GPS World*. 2 November 2016.

1. ^ [***a***](#cite_ref-Standard_0036_14-0) [***b***](#cite_ref-Standard_0036_14-1) [Department of Defense World Geodetic System 1984 - NGA.STND.0036_1.0.0_WGS84](https://earth-info.nga.mil/php/download.php?file=coord-wgs84) (Report).

1. **[^](#cite_ref-15)** ["Modern Geocentric Datum | GEOG 862: GPS and GNSS for Geospatial Professionals"](https://www.e-education.psu.edu/geog862/node/1801). *www.e-education.psu.edu*. Retrieved 31 December 2023.

1. **[^](#cite_ref-16)** ["Global Navigation Satellite System (GNSS)"](https://earth-info.nga.mil/index.php?dir=gnss&action=gnss). *Office of Geomantics*. January 2024. Retrieved 20 January 2024.

1. **[^](#cite_ref-17)** Australian Government - Geoscience Australia (20 March 2017). ["What are the limitations of using World Geodetic System 1984 in Australia?"](https://www.ga.gov.au/scientific-topics/positioning-navigation/wgs84). *www.ga.gov.au*. Retrieved 16 May 2022.

1. **[^](#cite_ref-18)** ["NGA Geomatics - WGS 84"](http://earth-info.nga.mil/GandG/update/index.php?dir=wgs84&action=wgs84#tab_egm2008). *earth-info.nga.mil*. Retrieved 19 March 2019.

1. **[^](#cite_ref-19)** ["World Magnetic Model"](https://www.ncei.noaa.gov/products/world-magnetic-model). *NCEI*. Retrieved 23 January 2020.

1. **[^](#cite_ref-20)** ["Evolution of the World Geodetic System 1984 (WGS 84) Terrestrial Reference Frame"](https://www.unoosa.org/documents/pdf/icg/2018/icg13/wgd/wgd_12.pdf) (PDF). Retrieved 15 January 2023.

1. **[^](#cite_ref-21)** ["World Geodetic System 1984 ensemble"](https://epsg.org/datum_6326/World-Geodetic-System-1984-ensemble.html). *EPSG Geodetic Parameter Dataset*. Retrieved 21 December 2022.

- This article incorporates [public domain material](/source/Copyright_status_of_works_by_the_federal_government_of_the_United_States) from websites or documents of the [National Geodetic Survey](/source/National_Geodetic_Survey).

## External links

- [NGA Standardization Document](https://earth-info.nga.mil/php/download.php?file=coord-wgs84#.pdf) *Department of Defense World Geodetic System 1984, Its Definition and Relationships With Local Geodetic Systems* (2014-07-08)

- [DMA Technical Report 8350.2](https://apps.dtic.mil/sti/pdfs/ADA280358.pdf) *Department of Defense World Geodetic System 1984, Its Definition and Relationships With Local Geodetic Systems* (1991-09-01). This edition documents the original Earth Gravitational Model.

- [NGA webpage for WGS 84](http://earth-info.nga.mil/GandG/wgs84/)

- [*Geodesy for the Layman*, Chapter VIII, "The World Geodetic System"](http://www.ngs.noaa.gov/PUBS_LIB/Geodesy4Layman/TR80003E.HTM#ZZ11)

- [Spatial reference for EPSG:4326](https://epsg.org/crs_4326/WGS-84.html)

- [ANTEX (.atx) files that define IGS20](https://files.igs.org/pub/station/general/)

v t e Physical oceanography Waves Airy wave theory Ballantine scale Benjamin–Feir instability Boussinesq approximation Breaking wave Clapotis Cnoidal wave Cross sea Dispersion Edge wave Equatorial waves Gravity wave Green's law Infragravity wave Internal wave Iribarren number Kelvin wave Kinematic wave Longshore drift Luke's variational principle Miche criterion Mild-slope equation Radiation stress Rogue wave Draupner wave Rossby wave Rossby-gravity waves Sea state Seiche Significant wave height Soliton Stokes drift Stokes problem Stokes wave Swell Trochoidal wave Tsunami megatsunami Undertow Ursell number Wave action Wave base Wave height Wave nonlinearity Wave power Wave radar Wave setup Wave shoaling Wave turbulence Wave–current interaction Waves and shallow water one-dimensional Saint-Venant equations shallow water equations Wind fetch Wind setup Wind wave model Circulation Atmospheric circulation Baroclinity Boundary current Coriolis force Coriolis–Stokes force Craik–Leibovich vortex force Downwelling Eddy Ekman layer Ekman spiral Ekman transport El Niño–Southern Oscillation General circulation model Geochemical Ocean Sections Study Geostrophic current Global Ocean Data Analysis Project Gulf Stream Humboldt Current Hydrothermal circulation Langmuir circulation Longshore drift Loop Current Modular Ocean Model Ocean current Ocean dynamical thermostat Ocean dynamics Ocean gyre Overflow Princeton Ocean Model Rip current Subsurface ocean current Sverdrup balance Thermohaline circulation shutdown Upwelling Whirlpool Wind generated current World Ocean Circulation Experiment Tides Amphidromic point Earth tide Head of tide Internal tide Lunitidal interval Perigean spring tide Rip tide Rule of twelfths Slack tide Theory of tides Tidal bore Tidal force Tidal power Tidal race Tidal range Tidal resonance Tide gauge Tideline Landforms Abyssal fan Abyssal plain Atoll Bathymetric chart Carbonate platform Coastal geography Cold seep Continental margin Continental rise Continental shelf Contourite Guyot Hydrography Knoll Ocean bank Oceanic basin Oceanic plateau Oceanic trench Passive margin Seabed Seamount Submarine canyon Submarine volcano Plate tectonics Convergent boundary Divergent boundary Fracture zone Hydrothermal vent Marine geology Mid-ocean ridge Mohorovičić discontinuity Oceanic crust Outer trench swell Ridge push Seafloor spreading Slab pull Slab suction Slab window Subduction Transform fault Vine–Matthews–Morley hypothesis Volcanic arc Ocean zones Benthic Deep ocean water Deep sea Littoral Mesopelagic Oceanic Pelagic Photic Surf Swash Sea level Deep-ocean Assessment and Reporting of Tsunamis Global Sea Level Observing System North West Shelf Operational Oceanographic System Sea-level curve Sea level drop Sea level rise World Geodetic System Acoustics Deep scattering layer Ocean acoustic tomography Sofar bomb SOFAR channel Underwater acoustics Satellites Jason-1 OSTM/Jason-2 Jason-3 Related Acidification Argo Benthic lander Color of water DSV Alvin Marginal sea Marine energy Marine pollution Mooring National Oceanographic Data Center Ocean Explorations Observations Reanalysis Ocean surface topography Ocean temperature Ocean thermal energy conversion Oceanography Outline of oceanography Pelagic sediment Sea surface microlayer Sea surface temperature Seawater Science On a Sphere Stratification Thermocline Underwater glider Water column World Ocean Atlas Category Commons Oceans portal

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Adapted from the Wikipedia article [World Geodetic System](https://en.wikipedia.org/wiki/World_Geodetic_System) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/World_Geodetic_System?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.