Geocart Projections

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Eckert IV

Classifications

Geocart menu class: Pseudocylindric
Geocart family: Eckert
Pseudocylindric
Equal area

Graticule

Meridians: Central meridian is a straight line half as long as the Equator. Other meridians are equally spaced semiellipses, concave toward the central meridian. The outer meridians (180° east and west of the central meridian) are semicircles.
Parallels: Unequally spaced straight parallel lines, widest separation near the Equator. Perpendicular to the central meridian.
Poles: Lines half as long as the Equator
Symmetry: About the central meridian or the Equator

Scale

True along latitudes 40°30' N. and S. Constant along any given latitude; same for the latitude of opposite sign

Distortion

Free of distortion only at latitudes 40°30' N. and S. at the central meridian.

Usage

Thematic and other world maps in numerous atlases and textbooks and for sheet maps

Origin

Presented by Max Eckert (1868-1938) of Germany in 1906

Aspects

Like most projections, transverse and oblique aspects can be prepared, although they are seldom used in this case.

Similar projections

Eckert III has meridians positioned identically, but parallels are equally spaced. Putnins P2' has meridians that are only portions of semiellipses, but parallels are also spaced for equal area.

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.