GeoProjection

GeoProjection

is an option for GeoGraphics that specifies the cartographic projection to use for the map.

Details

  • GeoProjection can use any projection "proj" or {"proj",params}, where "proj" is any of the entities of GeoProjectionData and params are parameter rules like "StandardParallels"{33,60}. GeoProjectionData["proj"] gives the default values of the parameters for the projection "proj".
  • GeoGraphics[,GeoProjectionAutomatic] chooses a projection automatically. It will be "Mercator" for small scales, "LambertAzimuthal" for intermediate scales, and "Equirectangular" for large scales. It also chooses the "Centering" and "GridOrigin" parameters automatically.
  • The projection is applied to the geo background of the GeoGraphics map, as well as to its geo primitives, like GeoPath or GeoDisk.
  • AbsoluteOptions can be used to give explicit projection information for a GeoProjection with Automatic setting.

Examples

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Basic Examples  (5)

A world map is shown by default in the equirectangular projection:

Use the Albers projection with default parameters:

Use the Albers projection with custom parameters and draw the standard parallels:

Maps of Canada in different projections, all with a 10-degree graticule:

The near side of the Moon:

Scope  (3)

Perform projections with default or automatic parameters:

Find out which parameters were used for the projection:

Specify your own projection parameters:

Project geo primitives with different projections:

In the equirectangular projection, the disk center is in the middle of the end points of the geodesic path:

In the Lambert azimuthal projection, the geodesic looks almost straight and the geo disk circular:

Properties & Relations  (2)

When no explicit projection is requested, one is automatically chosen:

When one or more non-geo graphic primitives appear and no projection is explicitly requested, the equirectangular projection is always used:

Use GeoDisk, Line[{GeoPosition[], }], etc. to place correctly projected primitives on the map:

Alternatively, specify a projection explicitly to combine primitives with regular graphics on the same coordinate scale as projected geo graphics:

Study geo projection distortion of the graticules, the grid of lines of constant latitude and longitude:

Neat Examples  (1)

Use the gnomonic projection to map the surface of the Earth onto the faces of a polyhedron:

Project onto a dodecahedron:

Project onto an icosahedron:

Introduced in 2014
 (10.0)