Types of Map Projections

  • Mar 19, 2010
  • Rick Ingle

  There are four basic types of map projections:

  1. Conformal
Preserves: Shape
Distorts: Area
 
  1. Equal Area
Preserves: Area
Distorts: Shape, Scale or Angle (bearing)
 
  1. Equidistant
Preserves: Distances between certain points (but not all points)
Distorts: Other distances
 
  1. Azimuthal (True Direction)
Preserves: Angles (bearings)
Distorts: Area and shape

 

In addition, there are three basic classifications of projection surfaces:

 

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USGS_map_Albers_conic_tall

A conic projection, as its name implies, is based on a cone which either touches the surface of the globe in a circle, or intersects the globe in two circles, passing through it.

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USGS_map_mercator_cylindrical

A cylindrical projection is based on a flat surface, curved to make a cylinder into which the globe is placed so that the globe intersects the cylinder in either one circle (where the cylinder touches the outside of the globe, or two circles (where the cylinder intersects and passes through the globe).

 

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PlanarProjection

A planar projection transforms all or part of the spherical surface onto a plane based either on one point of contact with the globe, or a circle of contact with the globe where the plane passes through the globe.