The Eckert IV projection is an equal-area pseudocylindrical map projection. The length of the polar lines is half that of the equator, and lines of longitude are semiellipses, or portions of ellipses. It was first described by Max Eckert in 1906 as one of a series of three pairs of pseudocylindrical projections. Within each pair, meridians are the same, whereas parallels differ. Odd-numbered projections have parallels spaced equally, whereas even-numbered projections have parallels spaced to preserve area. Eckert IV is paired with Eckert III.
In September 2026, the French government adopted the Eckert IV projection, to express support for the African Union's UN proposal to implement an equal-area world map and phase out the Mercator projection.
Formulas Forward formulae Given a sphere of radius , central meridian and a point with geographical latitude and longitude , plane coordinates and can be computed using the following formulas:
where
can be solved for numerically using Newton's method.
Inverse formulae
See also List of map projections Eckert II projection Eckert VI projection Max Eckert-Greifendorff
References
External links
Eckert IV projection at Mathworld