Classifications
tessellating
conformal
Graticule
Meridians: Every 90th meridian is straight but bent at the equator. Other meridians are complex curves.
Parallels: Equator is a square, bent at the straight meridians. Other parallels are complex curves.
Poles: Points at the center of each hemispherical map.
Symmetry: About the central meridian or the equator.
Aspects
In normal form, the pole is at the center of a square. In transverse form, placing the pole at the midpoint of one side of a square results in the Guyou projection. Placing the pole at the corner of the square results in the Adams projection of a hemisphere in a square.
Scale
Varies considerably along each meridian and parallel.
Distortion
Great distortion of area, especially near each 90th meridian at the equator, where conformality fails.
Other features
Actually a “star” projection in the normal aspect. Shows a polar hemisphere conformally in a square and the world in a larger square. The first use of elliptic functions for a map projection.
Usage
Novelty whole-world maps.
Similar projections
Listed under Aspects above.
Origin
Presented by Charles Sanders Peirce (1839–1914) of the U.S. Coast and Geodetic Survey in 1879.
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.