View source for Geodesy

[[File:Geodetisch station1855.jpg|thumb|An old geodetic pillar (1855) at [[Ostend]], [[Belgium]]]]
[[File:Litography archive of the Bayerisches Vermessungsamt.jpg|thumb|A [[Munich]] archive with [[lithography]] plates of maps of [[Bavaria]]]]

'''Geodesy''', sometimes called '''geodetics''', is a [[science|scientific]] branch of [[geography]] which accurately measures the [[surface]] of the [[Earth]]. 
{{Geodesy}}

[[Friedrich Robert Helmert]] (1843{{ndash}}1917), who started the discipline, talked about measuring and mapping the surface of the earth. This includes its [[geometry|geometric]] description (the [[geoid]]) and the measurement and description of its [[gravitational field]]. 

Some people involved in the discipline look at [[geodynamics]], the [[Crust (geology)|crust]]s, the [[tide]]s, or the movement of the [[geographical pole]]s.

== Geodesy Media ==
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File:GPS antenna and receiver Mount Blue Sky Colorado 23 August 2023.png|A modern instrument for geodetic [[measurements]] using [[GNSS|satellites]]

File:Geoid undulation 10k scale.jpg|[[Geoid]], an approximation for the shape of the [[Earth]]; shown here with [[vertical exaggeration]] (10000 vertical scaling factor).

File:Surface of latitude ellipsoid cone.gif|[[Ellipsoid]] - a mathematical representation of the [[Earth]]. When mapping in geodetic coordinates, a latitude circle forms a truncated cone.

File:WGS84_mean_Earth_radius.svg|Equatorial ({{mvar|a}}), polar ({{mvar|b}}) and mean Earth radii as defined in the 1984 [[World Geodetic System]]

File:Datum Shift Between NAD27 and NAD83.png|Datum shift between [[NAD27]] and [[NAD83]], in metres

File:Elliptical coordinates grid.svg|2D grid for elliptical coordinates

File:An-illustration-of-height-measurement-using-satellite-altimetry.jpg|Height measurement using satellite altimetry

File:GPS satellite approaching 23 years on orbit (1060259).jpeg|[[GPS]] Block IIA satellite orbits over the [[Earth]].

File:Geodetic Control Mark.jpg|Geodetic Control Mark

File:Stephen Merkowitz NASA's Space Geodesy Project.webm|A NASA project manager talks about his work for the [[Space geodesy|Space Geodesy]] Project, including an overview of its four fundamental techniques: GPS, [[very-long-baseline interferometry|VLBI]], [[Lunar laser ranging|LLR]]/[[Satellite laser ranging|SLR]], and [[DORIS (geodesy)|DORIS]].
</gallery>
== Related pages ==
*[[Cartography]]


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[[Category:Geodesy| ]]