This post was motivated by a user’s question about working with models of the world of a different size. The area of a world map with 2 km wide equator
In[]:=
GeoGraphics["World",GeoProjection->{"Equirectangular","ReferenceModel"->Quantity[2,"Kilometers"]/(2Pi)},Frame->True]
Out[]=
In[]:=
GeoArea["World",GeoModel->Quantity[2.,"Kilometers"]/(2Pi)]
Out[]=
1.27324
2
km
The resulted unit depends on your location. You can use UnitConvert to change units or specify the unit system in input:
In[]:=
GeoArea["World",GeoModel->Quantity[2.,"Kilometers"]/(2Pi),UnitSystem->"Imperial"]
Out[]=
0.491601
2
mi
It is also possible to specify an ellipsoidal world by providing a pair {a, b} of semiaxes, always with a >= b :
In[]:=
GeoArea["World",GeoModel->Quantity[{2.,1.5},"Kilometers"]/(2Pi),UnitSystem->"Metric"]
Out[]=
1.06723
2
km