Geocart Projections

What is a projection?

Previous | Next

Adams hemisphere in a square




Meridians: Central meridian is straight. The 90th meridians are straight lines bent at the Equator. Other meridians are curved.
Parallels: Equator is straight. Other parallels are curved.
Poles: Points, in opposite vertices of a square
Symmetry: About the central meridian or the Equator


Varies along each meridian and each parallel


Great distortion of area at the poles or the intersection of the 90th meridians with the Equator. At these four points, conformality fails.

Other features

Hemisphere is enclosed in a square. World can be enclosed in a 2x1 rectangle.


Novelty map of a hemisphere


Presented by Oscar Sherman Adams (1874–1962) of the U.S. Coast and Geodetic Survey in 1925


One transverse aspect is the Peirce Quincuncial projection. Another transverse aspect is a rotation of the original projection. An oblique aspect is the Guyou projection.

Similar projections

Listed under Aspects above

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.