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Albers projection

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(Redirected from Albers conic projection)
Albers projection of the world with standard parallels 20°N and 50°N.
The Albers projection with standard parallels 15°N and 45°N, with Tissot's indicatrix of deformation
An Albers projection shows areas accurately, but distorts shapes.

The Albers equal-area conic projection, or Albers projection (named after Heinrich C. Albers), is a conic, equal area map projection that uses two standard parallels. Although scale and shape are not preserved, distortion is minimal between the standard parallels.

Official adoption

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The Albers projection is used by some big countries as "official standard projection" for Census and other applications.

Country Agency
Brazil federal government, through IBGE, for Census Statistical Grid [1]
Canada government of British Columbia[2]
Canada government of the Yukon[3] (sole governmental projection)
US United States Geological Survey[4]
US United States Census Bureau[4]

Some "official products" also adopted Albers projection, for example most of the maps in the National Atlas of the United States.[5]

Formulas

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For Sphere

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Snyder[5] describes generating formulae for the projection, as well as the projection's characteristics. Coordinates from a spherical datum can be transformed into Albers equal-area conic projection coordinates with the following formulas, where is the radius, is the longitude, the reference longitude, the latitude, the reference latitude and and the standard parallels:

where

Lambert equal-area conic

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If just one of the two standard parallels of the Albers projection is placed on a pole, the result is the Lambert equal-area conic projection.[6]

See also

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References

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  1. ^ "Grade Estatística" (PDF). 2016. Archived from the original (PDF) on 2018-02-19.
  2. ^ "Data Catalogue".
  3. ^ "Support & Info: Common Questions". Geomatics Yukon. Government of Yukon. Retrieved 15 October 2014.
  4. ^ a b "Projection Reference". Bill Rankin. Archived from the original on 25 April 2009. Retrieved 2009-03-31.
  5. ^ a b Snyder, John P. (1987). "Chapter 14: ALBERS EQUAL-AREA CONIC PROJECTION". Map Projections – A Working Manual. U.S. Geological Survey Professional Paper 1395. Washington, D.C.: United States Government Printing Office. p. 100. Archived from the original on 2008-05-16. Retrieved 2017-08-28.
  6. ^ "Directory of Map Projections". "Lambert equal-area conic".
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