Was the Peters map a fair fix for Mercator's bias, or a flawed campaign?

It depends whom you ask. Peters and his supporters saw a fairer picture of the world; cartographers saw an old projection sold with inaccurate claims. The Gall–Peters projection is a rectangular equal-area map: it keeps sizes right, but it distorts most shapes, and only the latitudes 45° north and south are undistorted. The Scottish clergyman James Gall first described it in 1855. The German historian Arno Peters devised a similar one independently in 1967 and presented it in 1973 as the 'Peters world map'.

Peters argued that Mercator greatly distorts relative sizes, making wealthy Europe and North America look very large next to poorer Africa and South America. Socially concerned groups, including the National Council of Churches and the magazine New Internationalist, were swayed. Critics pointed out that his campaign leaned on an inaccurate claim that his was the only 'area-correct' map. Some of the oldest projections, such as the sinusoidal, are equal-area, and hundreds more exist. He also claimed 'absolute angle conformality', which was inaccurate.

Cartographers reacted with hostility to his criticisms and to the inaccuracy and lack of novelty of his claims. They pointed to cartographers who had for a century objected to publishers' overuse of Mercator. They also noted an irony: Gall–Peters shows the mid latitudes, including Peters's native Germany, undistorted, at the expense of the low latitudes where more technologically underdeveloped nations lie.

The two camps never reconciled. Yet J. Brian Harley credited the Peters phenomenon with demonstrating the social implications of map projections.