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Polyconic projection class

From Wikipedia, the free encyclopedia
American polyconic projection of the world
Van der Grinten projection of the world.

Polyconic can refer either to a class of map projections or to a specific projection known less ambiguously as the American polyconic projection. Polyconic as a class refers to those projections whose parallels are all non-concentric circular arcs, except for a straight equator, and the centers of these circles lie along a central axis. This description applies to projections in equatorial aspect.[1]

Polyconic projections

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Some of the projections that fall into the polyconic class are:

A series of polyconic projections, each in a circle, was also presented by Hans Mauer in 1922,[3] who also presented an equal-area polyconic in 1935.[4]: 248  Another series by Georgiy Aleksandrovich Ginzburg appeared starting in 1949.[4]: 258–262 

Most polyconic projections, when used to map the entire sphere, produce an "apple-shaped" map of the world. There are many "apple-shaped" projections, almost all of them obscure.[2]

See also

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References

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  1. ^ An Album of Map Projections (US Geological Survey Professional Paper 1453), John P. Snyder & Philip M. Voxland, 1989, p. 4.
  2. ^ a b John J. G. Savard. "The Dietrich-Kitada Projection".
  3. ^ https://pubs.usgs.gov/pp/1453/report.pdf [bare URL PDF]
  4. ^ a b John P. Snyder (1993). Flattening the Earth: Two Thousand Years of Map Projections. ISBN 0-226-76747-7.
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