There is no such thing as a perfect map projection. Mathematically, it’s impossible to transform the approximately spherical surface of the Earth into a 2-dimensional map without distorting either the shapes or relative sizes of the features on its surface (or both). You have to make compromises somewhere. Of course, you can make a globe, but that compromises on being able to fit on a flat page or screen.

Image from xkcd

Traditionally, every time someone makes a rant about map projections, there’s a part at the beginning where they rag on the Mercator projection for making Greenland too big and Africa too small, thereby diminishing the importance of equatorial countries and thereby promoting cultural imperialism. I agree that this is a flaw with using the Mercator to represent the world as a whole. But these days, I don’t really see people using the Mercator to represent the world as a whole – at least not exclusively.

Mercator projection map

Sure, it’s the projection that Google Maps uses, but they have a good excuse. If you want to keep North at the top of the map at every point, you need to use a “cylindrical” projection. If you want to preserve the shape of any small region, you need a “conformal” projection. And all conformal cylindrical projections are variants of the Mercator.

So if you want to be able to zoom from the scale of continents to neighborhoods without having to recalculate the map, it’s the best choice. But yes, it does make the equator smaller and the poles bigger, by a pretty significant margin. In fact, the scale grows infinitely large as you approach the poles – which is why Antarctica has to be cut off.

OK, so the Mercator has some pluses, but it’s not great for representing the whole world. Can we do better?

There have been several attempts to “correct” the Mercator over the years, making a cylindrical projection that preserves the relative areas of different regions. These all come at the cost of doing a very bad job preserving those regions’ shapes.

Hobo-Dyer equal area projection map

But cylindrical projections aren’t the only option. A Google Image search for “world map” reveals a couple Mercator maps, and a couple with the related Miller projection, which distorts the poles a bit less at the cost of not quite preserving angles perfectly. But along with these two, there were some with the Robinson projection, which portrays the Earth as a cut-off ellipse.

Robinson projection map

Abandoning the rectangular shape gives you more flexibility, plus suggests the round shape of the Earth. You do have to compromise on direction (e.g. does Patagonia slant Southeast, Southwest, or due South?). But the Robinson still doesn’t preserve area perfectly. Can we “correct” the areas of the Robinson the way we can with the cylindrical maps?

Equal Earth projection map

Well, yes – yes you can. There’s a few ways to accomplish this, like changing the curves on the edge of the map or the vertical scale, leading to slightly different projections. Of these, I personally favor the Equal Earth projection from 2018, because it was specifically designed to look nice and has the added bonus of being easy to calculate. The African Union, whose continent particularly suffers from the Mercator’s distortions, has endorsed the map, too.

Again, there are no perfect projections. The Equal Earth isn’t even unique in being an equal-area map of its shape. But I would personally love to see the Equal Earth in more places. It might not change the world, but it would change the map.

Coming Soon: The most controversial person on Wikipedia, apparently

(Maps by Strebe on Wikimedia commons)