Cabbages and Kings:

What's in a map?

The African Union has joined African advocacy groups in calling for global organizations to change their map projections — but what's motivating the movement?

Source: Thebe Ikalafeng and Mark Mamidola's The Africa Re-Union — check it out once you finish this article!

In August, the African Union — a continental union of Africa’s 55 countries — endorsed the “Correct the Map” petition led by African advocacy groups such as Africa No Filter and Speak Up Africa. The petition calls for global organizations such as the BBC, the World Bank, and the United Nations to stop using the Mercator map projection (shown above) for their world maps, arguing that it massively distorts polar areas and makes Africa appear undersized and insignificant.

Wait, you say. What’s a map projection?

Quiet, you! This is my article and I want to talk about . . . you know what? That’s actually a good place to start.

Map projections

Making maps is tricky, chiefly because they’re a two-dimensional representation of a three-dimensional object — a sphere, shown on a piece of paper. It’s like getting off an orange peel in one piece and trying to make it perfectly flat — impossible.

The author demonstrates the cardinal difficulty of mapmaking while on a snack break.

In order to have a flat map, you have to project that curve onto a flat surface, and for the huge scale of a world map, that ultimately involves distorting (in some respect) the sizes and shapes of the landmasses — especially if, like most mapmakers, you want to have your map in one piece instead of forty thousand.

The Mercator Projection

The Mercator projection dates to 1569, when it was first devised by Flemish cartographer Gerardus Mercator. To visualize it, imagine a globe with a light inside that can project the shapes of the continents onto another surface. A Mercator projection is a sheet of paper wrapped around that globe in a cylindrical shape.

Note that actual maps are made with lots of complicated math, not a lit-up globe, but this is an easier way of picturing it. Source: Britannica.

This map was designed chiefly for navigation purposes — remember, it was 1569, the middle of the Age of Exploration. Its advantage is that all lines of latitude and longitude are rendered as straight lines, all meeting at right angles. For a sixteenth-century sea captain, or for that matter an anyth-century sea captain, this is massively useful, because it means that if you plot a straight line on a Mercator map, it will cross every meridian it encounters at the same oblique angle — this is called a rhumb line, which on most maps (but not the Mercator!) will be a curve (or a logarithmic spiral, to use the fancy term. A rhumb line is not the shortest distance between two points on the Earth’s surface. That’s an arc of a great circle, which is what you see when you connect two points on Google Maps (which uses the Mercator projection, and thus shows said arc as a curve).

A great circle line on Google Maps. Believe it or not, this is the shortest line between Parises (France and Texas).

However, a rhumb line is easier to set a course on, because a ship sailing a rhumb line is sailing at a constant compass bearing — a constant angle in relation to the poles — and it does not require frequent correction. For this reason, the Mercator projection dominated, and continues to dominate, marine and navigational maps — except those used in high latitudes. More on why in a moment.

Mercatorial Misuse

Useful though the Mercator projection may be to sailors, it has major disadvantages for students and regular people trying to learn more about the world. Consider the “lit-up globe” thought experiment again — the light that shines through areas near the poles will strike the paper at more of an angle, distorting and increasing the sizes of landmasses the farther you travel from the equator. The Arctic island of Greenland, for instance, appears on the Mercator projection as a huge icy wasteland as big as all of Africa. If, however, we were to drag Greenland down to Africa’s latitude, it would shrink to a fourteenth of the continent’s size.

It would probably shrink even more once the ice melted and irrigated the Sahara desert. Source: thetruesize.com

This is why even sailors don’t use the Mercator projection in high latitudes — they would drastically miscalculate the distances and directions they were traveling. We non-sailors can end up with an equally misleading (though less occupationally hazardous) picture of the world. (For one more illustration of how misleading the projection can be, visit Mercator: Extreme, where you can set any location as the “north pole” of maximum distortion.)

xkcd.com/2082/

In fairness to Gerardus Mercator, he never intended his navigational projection to be hung up in classrooms or displayed on websites for the geographical education of thousands of non-navigators. But it was, and as a result, argue the African groups advocating for a change, the Mercator’s overuse by map publishers has caused many people to underestimate the equator-tied Africa’s size — and its importance — relative to the wealthy and Mercator-swollen northern continents of North America and Europe. Speak Up Africa, one of the groups pushing for a better map, is a Senegal-based organization advocating for sustainable development in Africa. According to the Correct the Map page of Speak Up Africa’s website “The widespread use of the Mercator projection, which dramatically shrinks the continent’s true size, is more than a cartographic flaw. It is a visual injustice that reinforces harmful power dynamics, undermines Africa’s global significance, and perpetuates colonial legacies.”

Correcting Calamitous Cartography

Awareness of this problem isn’t new. Since the middle of the 20th century, educators and other displayers of maps have become more aware that the Mercator is massively inadequate for their purposes.

Many new and fascinating projections have been put forward, but the worst by far is the Gall-Peters projection, the chief purpose of which is to show every country at its correct relative size.

Some critics of the Gall-Peters projection have argued that, in its focus on minimizing size distortion, it unintentionally comes close to maximizing shape distortion. Other critics (such as myself) have pointed out, with less eloquence but more force, that “eww. It’s just awful. Everything is so stretched and drippy. Uggh.” It turned out that a map designed solely for political correctness was even less helpful for showing the world than a map designed for navigation.

Blearrgh. Source: Wikipedia, by user strebe

Ironically, in the rush to correct the Mercator’s overuse, the Gall-Peters enjoyed its own undeserved moment as the textbooks’ darling. In 2017, it became the standard world map projection for public schools in Boston, Massachusetts, reviving the 50-year-old on-again-off-again cartographic debate. Responding to the news and the backlash, cartographers Bojan Šavrič, Tom Patterson, and Bernhard Jenny created the Robinson-inspired Equal Earth projection — behold!

Imagining the many completely unimpressed non-nerds who will look at this picture. Source: Wikipedia, created by user strebe

The areas are more or less fully equal, but the shapes are still incredibly well-preserved and appealing. And of course — there in the center is Africa, now as it is: second only to Asia in size, a hemisphere-straddling giant. For this reason, widespread adoption of this projection, in textbooks, on websites, and even on the walls of coffee shops, is the goal of Speak Up Africa: “when we correct the map, we also correct the perception. We restore visibility. We reclaim space. And we pave the way for a new era of representation where Africa is seen as it truly is: vast, vibrant, and central to our shared global future.”

While the Equal Earth projection provides a more lucid picture of the world, it’s still not perfect, of course — landmasses to the east and west are slightly curved, and no equator-centered projection can ever show what Antarctica actually looks like — but maybe that’s one more reminder that the best map projection of all . . . isn’t a map.

Keep learning.

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Sebastian Weinkopf is a senior from Southern California, currently taking AP Government and Politics with Mr. Munson. He enjoys jiujitsu, reading, running, and controversy.

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