Classifications
pseudocylindric
Graticule
Meridians: Central meridian is a straight line half as long as the equator. Other meridians are equally spaced portions of ellipses concave toward the central meridian.
Parallels: Unequally spaced straight parallel lines. Perpendicular to the central meridian.
Poles: Lines half as long as the equator.
Symmetry: About the central meridian or the equator.
Scale
Constant along any given latitude; same for the latitude of opposite sign.
Distortion
Free of distortion nowhere. While not equal-area, areal inflation/deflation is low across most of the map except for the high latitudes, with angular deformation dominating.
Similar projections
Wagner VI is scaled larger and has equally spaced parallels.
Putniṇš P1´ has identical meridians, parallels with constant spacing, but is scaled slightly larger.
Robinson projection has rounder “shoulders”, proportionally longer pole lines, and is scaled a little smaller.
Origin
Presented by Karlheinz Wagner of Germany in 1949.