How do you make a map? The problem of flattening the Earth and why the UN is abandoning Mercator

Representing a sphere on a flat surface is a geometric challenge that humanity has tried to solve for more than 2,000 years. A map can faithfully preserve one or several properties of the Earth, such as distance, shape, direction, or area, but never all of them at the same time. There will always be some kind of distortion. In the case of the recent U.N. resolution, the issue with the Mercator projection, the map used in schools, textbooks, international organizations, and even GPS systems, lies in the size of the continents.

Invented in the 16th century for navigation, the Mercator projection perfectly preserves direction. Four centuries ago, it allowed sailors to cross oceans using only a compass, which explains its success. The trade-off is that it sacrifices proportional size, exaggerating regions closer to the poles. Other projections, by contrast, preserve area while distorting shape. By following Africa across a range of projections, we can compare how its size and shape relate to those of the other continents.

There are three main approaches to projecting a sphere onto a flat surface. One involves projecting the globe onto a cylinder, the method used by the Mercator projection. Projections of this type can represent the entire world in a single, uninterrupted rectangle, with minimal distortion around the equator. Toward the poles, however, the distortion becomes extreme.

Another alternative is to project the globe onto a cone. This method exaggerates shapes farther from the center, making it unsuitable for representing the entire globe. However, these projections are well suited to regions that extend east to west. The third option is to project the world onto a plane. Its main advantage is that directions from the central point to any other point on the map are exact, though this comes at the expense of shape.

Every world map is a trade-off between one property and another. Choosing the correct projection depends on the region to be represented and the message to be communicated. And it is an important decision. Maps are not simple depictions of places; they carry social weight that “influences how we conceive the importance, centrality or peripheral position of those places,” says Derek Alderman, a geographer at the University of Tennessee in Knoxville.

“A map is not just a map”

The widespread use of Mercator for nearly 450 years is what led the UN, in a historic vote led by Togo and backed by the African Union (AU), to change its recommended projection from Mercator to “one that more accurately represents the size of the continents,” such as Equal Earth. The latter, designed in 2018 by cartographers Bojan Šavrič, Tom Patterson and Bernhard Jenny, uses a mathematical formula that preserves the relative areas of territories, at the cost of deforming their shapes and distances.

“It might seem to be just a map, but in reality, it is not,” Selma Malika Haddadi, vice president of the AU Commission, told Reuters. According to the African Union, the Mercator projection fosters the false impression that Africa is “marginal,” despite being the world’s second-largest continent by area and home to more than 1 billion people. The AU argues that this perception has been perpetuated in the media, education and in the development and implementation of public policy.

Supporters of the resolution describe it as “a historic step toward accurate and equitable global cartographic representation.” The text, which is nonbinding, does not call for banning the Mercator projection or replacing it in applications such as air and maritime navigation. Instead, its aim is to promote a more equitable representation of the world through cartography.

The United States was the only country in the U.N. General Assembly to vote against the recommended change in map projection. In a statement issued afterward, its representative described the resolution as “superfluous.”

In practice, adopting the Equal Earth projection would reduce the apparent size of Northern Hemisphere countries such as the United States, Greenland, and Russia, a change the African Union has advocated since August 2025. Correct The Map, one of the campaign’s leading supporters, frames the issue this way: “If we got something as basic as Africa’s size wrong for this long, what else about Africa have we simply accepted without questioning?”

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