Classifications
cylindric
equidistant
Graticule
Meridians: Equally spaced straight parallel lines more than half as long as the equator.
Parallels: Equally spaced straight parallel lines, perpendicular to and having wider spacing than meridians.
Poles: Straight lines equal in length to the equator.
Symmetry: About any meridian or the equator.
Scale
True along two standard parallels equidistant from the equator and along all meridians.
Too small along the equator but increases with distance from the equator along the parallels.
Constant along any given parallel; same scale at the parallel of opposite sign.
Distortion
Infinitesimally small circles on the globe (indicatrices) are circles on the map at latitudes 30°N and S. For this choice of standard parallels. Elsewhere, area and local shape are distorted.
Other features
Simple modification of Plate Carree having east-west compression.
Conceptually projected onto a cylinder secant to the globe along the chosen standard parallels.
Not perspective.
Usage
Simple outline maps of regions or of the world or for index maps Used only in the spherical form.
Origin
Marinus of Tyre about A.D. 100.
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.