Geocart Projections

What is a projection?

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Geocart menu class: Azimuthal
Modified azimuthal
Equal area


Polar aspect:
Meridians: Semicircles if extended to a world map
Parallels: Concentric circles
Poles: Central pole is a point; other pole is a circle
Symmetry: Radial about the central pole


Correct along meridians


Considerable distortion of shape at the map edge


A novelty map that, in its polar aspect, has semicircular meridians arranged in a pinwheel


Presented by H. Wiechel in 1879
Aspects Normally only polar

Similar projections

Lambert Azimuthal Equal-Area projection has the same spacing of parallels in the polar aspect, but the meridians are straight.
Ginzburg 111 is a general series of pseudoazimuthal projections developed by C.A. Ginzburg of the Soviet Union in 1952. The lines of constant distortion are ovals rather than the usual circles of azimuthal projections. This feature is achieved by the manner in which the lines of constant initial azimuth are curved. The projection series has been used only in the oblique or equatorial aspect.

Description adapted from J.P. Snyder and P.M. Voxland, An Album of Map Projections, U.S. Geological Survey Professional Paper 1453. United States Government Printing Office: 1989.