({{, (RefLink[GeoModel, paclet:ref/GeoModel]) 
is an option for (RefLink[GeoGraphics, paclet:ref/GeoGraphics]) that specifies the reference body or model for it for the purposes of geodetic computations and map drawing.}})

OpenersNotesSection(Spacer1)Details

The following settings can be used:

The semiaxes lengths a, b in GeoModel->{a,b} and the radius r in GeoModel->r can be given either as numbers in meters or (RefLink[Quantity, paclet:ref/Quantity]) lengths.

OpenersPrimaryExamplesSection(Spacer1)Examples  (5)

OpenersExampleSection0(Spacer1)Basic Examples  (2)

Use the default (ellipsoidal) model of the Earth, where geodesics do not close:

GeoGraphics[{Thin,GeoPath[{(Entity["New York City", Entity["City",{"NewYork","NewYork","UnitedStates"}], "Entity[\"City\", {\"NewYork\", \"NewYork\", \"UnitedStates\"}]", "city"]),GeoDisplacement[{(QuantityUnit[(10^5)]),"NW"}]}]},GeoCenter->(Entity["New York City", Entity["City",{"NewYork","NewYork","UnitedStates"}], "Entity[\"City\", {\"NewYork\", \"NewYork\", \"UnitedStates\"}]", "city"]),GeoRange->(QuantityUnit[200])]

Use a spherical model of the Earth, where geodesics close:

GeoGraphics[{Thin,GeoPath[{(Entity["New York City", Entity["City",{"NewYork","NewYork","UnitedStates"}], "Entity[\"City\", {\"NewYork\", \"NewYork\", \"UnitedStates\"}]", "city"]),GeoDisplacement[{(QuantityUnit[(10^5)]),"NW"}]}]},GeoCenter->(Entity["New York City", Entity["City",{"NewYork","NewYork","UnitedStates"}], "Entity[\"City\", {\"NewYork\", \"NewYork\", \"UnitedStates\"}]", "city"]),GeoRange->(QuantityUnit[200]),GeoModel->(QuantityUnit[3956.56])]

Use Mars as a reference model:

GeoGraphics[GeoModel->(Entity["Mars", Entity["Planet","Mars"], "Entity[\"Planet\", \"Mars\"]", "planet"]),GeoProjection->"Bonne",GeoRange->All,GeoGridLines->(QuantityUnit[15]),GeoGridLinesStyle->Directive[Thin,Orange,Opacity[0.5]],Background->Black,PlotRangePadding->0.2]

Use the Moon:

GeoGraphics[GeoModel->(Entity["Moon", Entity["PlanetaryMoon","Moon"], "Entity[\"PlanetaryMoon\", \"Moon\"]", "planetary moon"]),GeoRange->All,GeoProjection->{"LambertAzimuthal","Centering"->{90,0}},GeoGridLines->Quantity[30,"AngularDegrees"],GeoGridLinesStyle->Directive[Thin,Blue,Opacity[0.5]],Background->Black,PlotRangePadding->0.2]

OpenersExampleSection2(Spacer1)Applications  (1)

Store the coordinates/sizes of the lunar maria:

maria=(EntityClass["Moon maria", EntityClass["SolarSystemFeature","MoonMare"], "EntityClass[\"SolarSystemFeature\", \"MoonMare\"]", "solar system features"]);
coords=EntityValue[maria,"Position"];
sizes=EntityValue[maria,"Size"]/2;
data=Transpose[{coords,sizes,EntityList[maria]}];

Plot the maria together with their names (as tooltips):

GeoGraphics[{GeoStyling[Directive[Opacity[.6],RandomColor[],EdgeForm[Black]]],Tooltip[GeoDisk[#1,#2],CommonName[#3]]}&@@@data,GeoModel->(Entity["Moon", Entity["PlanetaryMoon","Moon"], "Entity[\"PlanetaryMoon\", \"Moon\"]", "planetary moon"]),GeoRange->All,GeoProjection->"Mollweide",GeoGridLines->(QuantityUnit[15]),GeoGridLinesStyle->Directive[Thin,Blue,Opacity[0.4]],Background->Black,PlotRangePadding->0.2,ImageSize->Medium]

OpenersExampleSection3(Spacer1)Properties & Relations  (2)

Show unclosed geodesics, which are one consequence of the nonsphericity of the Earth:

GeoGraphics[{Thin,GeoPath[{{0,0},(Quantity[1 (10^6), "km", kilometers, "Kilometers"]),(QuantityPostfix[45, "°", degrees, "AngularDegrees"])}]},GeoRange->"World"]

Compare with a spherical model:

GeoGraphics[{Thin,GeoPath[{{0,0},(Quantity[1 (10^6), "km", kilometers, "Kilometers"]),(QuantityPostfix[45, "°", degrees, "AngularDegrees"])}]},GeoRange->"World",GeoModel->(Quantity[6378, "km", kilometers, "Kilometers"])]

Large disks accumulating around the antipodal point, using a spherical model of the Earth:

GeoGraphics[Table[GeoDisk[GeoPosition[{0,80}],r],{r, 19970000,20030000,10000}],GeoProjection->"Equirectangular",GeoRange->{{-0.7,0.7},{-100.7,-99.3}},GeoModel->GeodesyData["ITRF00","SemimajorAxis"]]

The default reference model is an ellipsoid:

GeoGraphics[Table[GeoDisk[GeoPosition[{0,80}],r],{r, 19970000,20030000,10000}],GeoProjection->"Equirectangular",GeoRange->{{-0.7,0.7},{-100.7,-99.3}}]

({{DocumentationFooterIconsRelatedFunction.png, ({{See Also}, {(RefLink[GeoGraphics, paclet:ref/GeoGraphics])  ▪  (RefLink[GeoPosition, paclet:ref/GeoPosition])  ▪  (RefLink[GeodesyData, paclet:ref/GeodesyData])  ▪  (RefLink[PlanetData, paclet:ref/PlanetData])  ▪  (RefLink[PlanetaryMoonData, paclet:ref/PlanetaryMoonData])  ▪  (RefLink[GeoBounds, paclet:ref/GeoBounds])  ▪  (RefLink[GeoBoundingBox, paclet:ref/GeoBoundingBox])  ▪  (RefLink[GeoPath, paclet:ref/GeoPath])  ▪  (RefLink[GeoDisk, paclet:ref/GeoDisk])}})}})

({{DocumentationFooterIconsRelatedTutorial.png, ({{Tutorials}, {▪(RefLinkPlain[GeoGraphics, paclet:tutorial/GeoGraphics])}})}})

({{DocumentationFooterIconsRelatedGuide.png, ({{Related Guides}, {▪(RefLinkPlain[Maps & Cartography, paclet:guide/MapsAndCartography])}, {▪(RefLinkPlain[Earth Sciences: Data & Computation, paclet:guide/EarthSciencesDataAndComputation])}})}})