Geocart Projections

What is a projection?

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Robinson

Parameters: Computational style

Classifications

Geocart menu class: Pseudocylindric
Pseudocylindric
Neither conformal nor equal area

Graticule

Meridians: Central meridian is a straight line 0.51 as long as the Equator. Other meridians resemble elliptical arcs, are equally spaced, and are concave toward the central meridian.
Parallels: Straight parallel lines, equally spaced between latitudes 38° N. and S.; space decreases beyond these limits.
Poles: Lines 0.53 as long as the Equator
Symmetry: About the central meridian or the Equator

Scale

True along latitudes 38° N. and S. Constant along any given latitude; same for the latitude of opposite sign

Distortion

No point is completely free of distortion, but distortion is very low within about 45° of the center and along the Equator. Considerable distortion near the poles.

Usage

By Rand McNally in Goode’s Atlas for thematic world maps and in numerous other publications

Origin

Presented by Arthur H. Robinson (1915- ) of the University of Wisconsin in 1963, at the request of Rand McNally and Company.
Uses tabular coordinates rather than mathematical formulas to make the world map “look” right.

Other names

Orthophanic (“right appearing”)

Similar projections

Putnins P2', an equal-area projection on which meridians are elliptical arcs
In 1968, Janos Baranyi presented seven pseudocylindrical projections characterized by various graduated tabular spacings of the parallels. The poles are usually points but occasionally are lines, and the outer meridians 180° from the central meridian are circular arcs combined in some cases with straight lines. His projections are neither equal area nor conformal.

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.