Directory of Map Projections

What is a projection?

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equal-area polynomial

Parameters: Note, Coefficient a, Coefficient b, Coefficient c, Coefficient d, Coefficient e




Meridians: Complex curves equally spaced along parallels.
Parallels: Straight parallel lines.
Poles: Points.
Symmetry: Symmetric east-west. Symmetric north-south when b and d = 0.

Limiting forms

Sinsoidal, when a = 1.0 and the others = 0.


Coefficients a, b, c, d, e, each for a successively higher power of the latitude. Generally these values should be 1.0 or less, and the higher the letter, the smaller the value.


Developed by Daniel “daan” Strebe (1962–) in 2015. However, the concept is straightforward, with several polynomial developments appearing in the literature, typically for optimizing the projection in some way.

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