List of Projections for Use with WorldMap
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Description
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The Display command of the WorldMap object can display maps of the world using various projections by specifying the projection=proj keyword option.
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Some projections accept additional parameters for the central meridian () and/or the standard parallel ().
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Examples in all sections below use the WorldMap object with no point stored:
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m:=DataSets:-Builtin:-WorldMap();
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Geographic
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The Geographic projection directly maps longitude and latitude pairs to and coordinates in the map.
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It is a special case of the Equirectangular projection with the standard parallel () equal to 0 degrees.
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Display(m,projection=Geographic);
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Cassini
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The Cassini projection is the transverse aspect of the Geographic projection.
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The Cassini projection can accept an additional parameter for the central meridian ().
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If no parameter is specified, the resulting projection is equivalent to Cassini(0).
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Display(m,projection=Cassini);
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Mercator
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The Mercator projection is a conformal cylindrical map projection which is widely used for nautical purposes.
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It greatly exaggerates areas far from the equator, and the poles are projected to infinity, so the map must be truncated near the poles.
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Display(m,projection=Mercator);
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TransverseMercator
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The TransverseMercator projection is the transverse aspect of the Mercator projection.
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It delivers accurate scales near the central meridian.
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Display(m,projection=TransverseMercator);
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MillerCylindrical
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The MillerCylindrical projection is a compromise cylindrical map projection that is intended to look similar to the Mercator projection while displaying the poles.
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The MillerCylindrical projection is the default projection used by the Display command.
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Display(m,projection=MillerCylindrical);
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CylindricalEqualArea
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The CylindricalEqualArea projection is a family of cylindrical and equal area projections.
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The general CylindricalEqualArea projection can accept an additional parameter for the standard parallel ().
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If no parameter is specified, the resulting projection is the HoboDyer projection.
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Supported special cases include LambertCylindricalEqualArea, Behrmann, SmythEqualSurface, TrystanEdwards, HoboDyer, GallPeters, and Balthasart. The value of the standard parallel for these projections is listed in the table below.
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Projections
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LambertCylindricalEqualArea
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0
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Behrmann
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30
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SmythEqualSurface
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37 + 4 / 60 + 17 / 3600 (that is, 37° 4' 17")
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TrystanEdwards
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37.4
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HoboDyer
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37.5
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GallPeters
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45
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Balthasart
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50
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Display(m,projection=CylindricalEqualArea(37.5));
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LambertAzimuthalEqualArea
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The LambertAzimuthalEqualArea projection maps the earth onto a disk, and it preserves areas of all regions.
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The LambertAzimuthalEqualArea projection can accept two parameters for the central meridian () and the standard parallel ().
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If no parameter is specified, the resulting projection is the equatorial aspect of the LambertAzimuthalEqualArea projection.
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The point (,) becomes the center of the projected map.
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Display(m,projection=LambertAzimuthalEqualArea(20.4, -15));
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AzimuthalEquidistant
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The AzimuthalEquidistant projection can accept two parameters for the central meridian () and the standard parallel ().
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If no parameter is specified, the resulting projection is the north pole aspect of the AzimuthalEquidistant projection.
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The point (,) becomes the center of the projected map.
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Distances from the center to all other points are preserved.
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Display(m,projection=AzimuthalEquidistant(0,90));
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VanderGrinten
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The VanderGrinten projection is a compromise projection that maps the earth onto a circle. The polar regions exhibit great distortions.
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It was used by the National Geographic Society from 1922 to 1988.
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Display(m,projection=VanderGrinten);
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Bonne
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The Bonne projection is a pseudoconical equal area projection which is an intermediate between the Werner projection and the Sinusoidal projection.
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The Bonne projection can accept two parameters for the central meridian () and the standard parallel ().
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If no parameter is specified, the resulting projection is equivalent to Bonne(0,45).
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Display(m,projection=Bonne(0,45));
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Bottomley
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The Bottomley projection is a pseudoconical equal area projection that is designed as a better looking alternative to the Bonne projection.
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The Bottomley projection can also be seen as an intermediate between the Werner projection and the Sinusoidal projection.
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The Bottomley projection can accept an additional parameter for the standard parallel ().
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If no parameter is specified, the resulting projection is equivalent to Bottomley(45).
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Display(m,projection=Bottomley(45));
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Werner
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The Werner projection is a limiting case of both the Bonne and the Bottomley projection.
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It is equivalent to Bonne(0,90) and Bottomley(90).
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Display(m,projection=Werner);
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Sinusoidal
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The Sinusoidal projection is also a limiting case of both the Bonne and the Bottomley projection.
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The Sinusoidal projection can accept an additional parameter for the central meridian ().
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The Sinusoidal(0) projection is equivalent to Bottomley(0). The Sinusoidal() projection is equivalent to Bonne(, 0).
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If no parameter is specified, the resulting projection is equivalent to Sinusoidal(0).
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Display(m,projection=Sinusoidal(-12));
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Robinson
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The Robinson projection is a pseudocylindrical compromise projection that is designed to produce a nice looking map for the entire world.
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It was used by the National Geographic Society from 1988 to 1998.
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Display(m,projection=Robinson);
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WinkelTripel
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The WinkelTripel projection is a pseudoazimuthal compromise projection that tries to minimize area, direction, and distance distortions all at the same time.
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It has been used by the National Geographic Society since 1998.
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Display(m,projection=WinkelTripel);
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Globe
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The Globe projection displays a 3-D plot of the earth as a sphere.
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Display(m,projection=Globe);
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