## Directory of Map Projections

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Lambert equal-area cylindric

Classifications

cylindric
equal-area
perspective

Graticule

Meridians: Equally spaced straight parallel lines 0.32 as long as the equator.
Parallels: Unequally spaced straight parallel lines, farthest apart near the equator, perpendicular to meridians.
Poles: Straight lines equal in length to the equator.
Symmetry: About any meridian or the equator.

Aspects

Normal is described here. Transverse and oblique aspects are rarely used but are recommended for equal-area mapping of predominantly north-south regions or regions extending obliquely.

Scale

True along the equator.
Increases with distance from the equator in the direction of parallels and decreases in the direction of meridians to maintain equal-area.
Same scale at the parallel of opposite sign.

Distortion

Infinitesimally small circles (indicatrices) of equal size on the globe are ellipses except at the equator, where they are circles. The areas of all the indicatrices are the same. Thus, there is shape distortion but no area distortion. Shape distortion in polar regions is extreme.

Other features

Simple graticule, perspectively projected in lines perpendicular to the axis onto a cylinder wrapped around the globe tangent to the equator.

Usage

Minimal except to describe basic principles in map projection texts.
Prototype for Behrmann and other modified cylindric equal-area projections.
Recommended for equal-area mapping of regions predominantly bordering the equator.

Similar projections

If meridians are compressed relative to parallels and if the spacing of parallels is increased in inverse proportion, other cylindric equal-area projections result, and the standard parallel changes. The extreme case, in which the poles are standard parallels, consists of a single vertical line, infinitely long.
Named examples are as follows:.
Behrmann
Gall Orthographic.
Trystan Edwards.
Peters
(See Behrmann cylindric equal-area projection for the differences.).

Origin

Presented by Johann Heinrich Lambert (1728–77) of Alsace in 1772.

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.