A cylindrical projection that is equal-area. Also known as simply the Cylindrical Equal Area projection. The projection upon which the even more distorting Gall projection is based.
No distortion of scale and shape at the standard parallels of the normal aspect but great distortion of shape and scale otherwise.
Substantial shape and scale distortion near points 90 degrees from central line resulting in vertical exaggeration of Equatorial regions with compression of regions in middle latitudes and extreme vertical aspect compression in higher latitudes.
Most frequently used as a textbook example of the most easily constructed equal-area projection. Even with various proposed modifications (such as the Gall) distortions are so great that there has been little use of any of the forms for world maps by professional cartographers, many of whom have strongly criticized the intensive promotion in the non-cartographic community which has accompanied the political promotion of the re-named Gall modification (the infamous, viciously political Peters projection).
Despite the shape distortion in some portions of a world map, this projection is well suited for equal-area mapping of regions which are predominantly north-south in extent, which have an oblique central line, or which lie near the Equator.
Devised by Johann Heinrich Lambert in 1772 and is the fourth of seven projections invented by him. Lambert described the transverse aspect which has very rarely been used. Even the normal aspect has been rarely used. A series of modifications were proposed by Gall in 1855, Behrmann in 1910 and others.
Very similar projections were offered by Trystan Edwards of England in 1953 and a re-named copy of the Gall by propagandist Arno Peters of Germany in 1967 who falsely claimed to have invented the Gall projection along with other false claims. The Edwards and Peters claims were presented as revolutionary and original concepts rather than as modifications or plagiarisms of the prior projections.