Gall–Peters projection

The Gall–Peters projection is a rectangular map that preserves area accurately across the globe, but like all equal-area projections, it heavily distorts the shapes of most landmasses. It belongs to the cylindrical equal-area family, with its standard parallels—the lines where distortion is absent—set at 45° north and south. The projection takes its name from James Gall and Arno Peters. Gall first described it in 1855 at a meeting of the British Association for the Advancement of Science, where he presented it alongside two other projections, calling it “orthographic.” He formally published his work in 1885 in the Scottish Geographical Magazine.

The projection’s spacing between parallels is a constant multiple of those in the orthographic projection. Arno Peters independently devised a similar projection in 1967, presenting it in 1973 as the “Peters world map.” His original description contained a geometric error implying standard parallels of 46°02′ north and south, but the accompanying text made clear his intent was 45° north and south, making his projection identical to Gall’s. The name “Gall–Peters projection” was first used by Arthur H. Robinson in a 1986 pamphlet from the American Cartographic Association. Before 1973, it was known, when mentioned at all, as “Gall’s orthographic.” During the subsequent controversy, cartographic articles often used one name or the other while acknowledging both; in recent years, “Gall–Peters” has become dominant.

Peters world map controversy

The projection achieved notoriety in the late 20th century as the centerpiece of a debate over the political implications of map design. Peters promoted it as a superior alternative to the Mercator projection, arguing that Mercator made wealthy Europe and North America appear large relative to poorer Africa and South America. This swayed socially concerned groups like the National Council of Churches and New Internationalist magazine. However, Peters inaccurately claimed his was the only “area-correct” map, ignoring many older equal-area projections, and also falsely asserted it had “absolute angle conformality,” “no extreme distortions of form,” and was “totally distance-factual.” The cartographic community reacted with hostility to these inaccuracies and to Peters’s criticisms, noting that many cartographers had long advocated against overuse of the Mercator.