Eckert III+IV

Classifications

pseudocylindric

Graticule

Meridians: Central meridian is a straight line half as long as the equator. Other meridians are equally spaced semiellipses, concave toward the central meridian. The outer meridians (180° east and west of the central meridian) are semicircles.
Parallels: Straight parallel lines with variable spacing. Perpendicular to the central meridian.
Poles: Lines half as long as the equator.
Symmetry: About the central meridian or the equator.

Distortion

No point is free of distortion. Distortion is moderate throughout except toward the poles, where it is severe.

Similar projections

Robinson projection has less rounded “shoulders”. Eckert III and Eckert IV have the same perimeter.

Origin

Synthesized from the average of the Eckert III and Eckert IV projections by Daniel “daan” Strebe in 1992 to approximate the appearance of the Robinson projection without using an interpolation table.

Description adapted from J.P. Snyder and P.M. Voxland, An Album of Map Projections, U.S. Geological Survey Professional Paper 1453. United States Government Printing Office: 1989.