The WGS 84 datum surface is an oblate spheroid with equatorial radius a = m at the equator and flattening f = 1/. The refined value of the WGS 84 gravitational constant (mass of Earth's atmosphere included) is GM = ×108 m3/s2 . The angular velocity of the Earth is defined to be ω = 72.92115×10−6 rad/s . This leads to several computed parameters such as the polar semi-minor axis b which equals a × (1 − f) = m , and the first eccentricity squared,  e2 = ×10−3. External links Geodesy for the Layman, Chapter VIII, "The World Geodetic System" NIMA Technical Report TR8350.2 Department of Defense World Geodetic System 1984, Its Definition and Relationships With Local Geodetic Systems,  Third Edition, National Geospatial-Intelligence Agency. This is the official publication of the standard, including addenda. Note this report actually documents the EGM 96 model (a revision of WGS 84). The original WGS 84 is documented in versions prior to 1996. Main NGA (was NIMA) page on Earth gravity models Description of the difference between the geoid and the ellipsoid from the US NOAA National Geodetic Survey GEOID page NASA GSFC Earth gravity page GeographicLib provides a utility GeoidEval (with source code) to evaluate the geoid height for the EGM84, EGM96, and EGM2008 earth gravity models. Here is an online version of GeoidEval. Spatial reference for EPSG:4326
The WGS 84 datum surface is an oblate spheroid with equatorial radius = at the equator and flattening = 1/. The refined value of the WGS 84 gravitational constant (mass of Earth's atmosphere included) is = . The angular velocity of the Earth is defined to be = . This leads to several computed parameters such as the polar semi-minor axis which equals = , and the first eccentricity squared, math| e2 = . External links Geodesy for the Layman, Chapter VIII, "The World Geodetic System" NIMA Technical Report TR8350.2 Department of Defense World Geodetic System 1984, Its Definition and Relationships With Local Geodetic Systems, '' Third Edition, National Geospatial-Intelligence Agency. This is the official publication of the standard, including addenda. Note this report actually documents the EGM 96 model (a revision of WGS 84). The original WGS 84 is documented in versions prior to 1996. Main NGA (was NIMA) page on Earth gravity models Description of the difference between the geoid and the ellipsoid from the US NOAA National Geodetic Survey GEOID page NASA GSFC Earth gravity page GeographicLib provides a utility GeoidEval (with source code) to evaluate the geoid height for the EGM84, EGM96, and EGM2008 earth gravity models. Here is an online version of GeoidEval. Spatial reference for EPSG:4326
D
a
D
m
D
f
D
GM
D
×108 m3/s2
D
ω
D
72.92115×10−6 rad/s
R
b which equals a × (1 − f)
which equals
D
m
A
math|
R
×10−3.
.
A
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