From Gall-Peters to Equal Earth: The 200-Year Quest for Equal-Area Cartography

1. Early Pioneers: Mollweide & Albers (1805)

The mathematical quest to represent the entire world with true proportional surface area began in earnest during the 19th century.

In 1805, German mathematician and astronomer Karl Brandan Mollweide published an elliptical equal-area pseudocylindrical projection. Mollweide curved the outer boundary of the world map into a 2:1 ellipse, making it the first widely used equal-area world map for global thematic data.

That same year, Heinrich Christian Albers introduced the Albers Equal-Area Conic projection, which became the authoritative standard for mapping mid-latitude nations like the United States, China, and India because of its near-zero distortion across vast longitudinal belts.

2. The Gall-Peters Controversy (1973)

In 1973, German historian Arno Peters held a press conference in Bonn, announcing what he claimed was a revolutionary new map that showed the world "fairly" for developing nations in the Global South. (In reality, Scottish clergyman James Gall had already invented and published the exact same projection in 1855, hence the modern name Gall-Peters projection).

Peters forcefully attacked the Mercator projection, arguing that Mercator was a symbol of Eurocentric imperialism that promoted racism by visually diminishing tropical continents like Africa and South America.

While Peters’s social advocacy for equal-area mapping gained widespread support from UNESCO, church organizations, and non-profits, professional cartographers were horrified by the severe geometric distortion of Gall-Peters:

• Severe Tropical Elongation: Tropical continents (Africa and South America) were stretched vertically by more than 200%, giving them a "wet laundry hanging on a clothesline" appearance.
• Severe Polar Squashing: High-latitude regions (Canada, Russia, Greenland) were compressed horizontally into flat, rectangular strips.

3. The Compromise Era: Robinson & Winkel Tripel

Frustrated by the harsh geometric shapes of Gall-Peters and the extreme polar inflation of Mercator, American cartographer Arthur H. Robinson developed the Robinson projection in 1963. In 1988, the National Geographic Society adopted the Robinson projection for all official world maps, before switching to Oswald Winkel’s 1921 Winkel Tripel projection in 1998.

However, both Robinson and Winkel Tripel are compromise projections: they are neither conformal nor equal-area. While they look balanced and pleasing to the eye, they still distort real country surface areas by 10% to 25%, leaving educators without an aesthetically pleasing strictly equal-area world map.

4. The 2017 Boston Catalyst & the 2018 Breakthrough

In March 2017, the Boston Public School District announced it was phasing out Mercator wall maps in favor of Gall-Peters to promote racial and geographic equity. The move reignited the global debate: educators wanted equal-area fairness, but hated the extreme distortion of Gall-Peters.

Three renowned cartographers—Bojan Šavrič, Bernhard Jenny, and Tom Patterson—decided to solve this dilemma once and for all:

"We sought to create an equal-area map projection that looks like Robinson—with smooth, natural continental curves—while guaranteeing 100% mathematical equality of surface area."

In August 2018, they published the Equal Earth map projection in the International Journal of Geographical Information Science.

5. Summary of World Map Evolution