Directory of Map Projections

What is a projection?

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equal-area pseudoconic

Parameters: Latitude of origin, φ₁, φ₂, φ₃, Weight of Bonne


A very configurable pseudoconic, equal-area projection that gives a continuum between Albers and Bonne projections.




Meridians: Complex curves except for straight central meridian.
Parallels: Portions of circles.
Poles: Points.


φ₁, φ₂, φ₃: These configure the projection’s regions of low distortion. In general, φ₁ and φ₂ relate closely to the region of low distortion. φ₃ is often more abstract; it is used to “pull” the central region of low distortion upward or downward.
Weight of Bonne: 0 gives the Albers projection; 1 gives the Bonne projection; values between give intermediate projections on the continuum.

Similar projections

The Albers-Bonne homotopy has many similar configurations.
Albers is a limiting form.
Bonne is a limiting form.


Presented by Daniel “daan” Strebe in 2015.

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