The Eckert-Greifendorff projection is an equal-area map projection described by Max Eckert-Greifendorff in 1935.
Unlike his previous six projections, it is not pseudocylindrical.
Directly inspired by the Hammer projection, Eckert-Greifendorff suggested the use of the equatorial form of the Lambert azimuthal equal-area projection instead of Aitoff's use of the azimuthal equidistant projection: where laeax and laeay are the x and y components of the equatorial Lambert azimuthal equal-area projection.
Written out explicitly: The inverse is calculated with the intermediate variable The longitude and latitudes can then be calculated by where λ is the longitude from the central meridian and φ is the latitude.
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