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 the meridians.
Poles: Straight lines equal in length to the Equator.
Symmetry: About any meridian or the Equator.
This is a projection onto a cylinder secant at the standard parallels. Distortion of both shape and area increase with distance from the standard parallels. Scale is true along all meridians (i.e., it is equidistant) and the standard parallels and is constant along any parallel and along the parallel of opposite sign.
For cylindrical projections, only one standard parallel is specified. The other standard parallel is the same latitude with the opposite sign. For this projection, any latitude can be chosen; the default is arbitrarily set to 30º.
This projection was first used by Marinus of Tyre about A.D. 100. Special forms of this projection are the Plate Carrée, with a standard parallel at 0º, and the Gall Isographic, with standard parallels at 45ºN and S. Other names for this projection include Equirectangular, Rectangular, Projection of Marinus, La Carte Parallélogrammatique, and Die Rechteckige Plattkarte.