Africa? Pretty big, but just how big? Imagine it in your head. Is it:
- About the same size as Greenland?
- A little bigger than South America?
- Bigger than China, India, the contiguous United States, and large chunks of Europe—combined?
Look at the map above if you want a hint.
Except, that map is lying to you. Africa, at just under 11.73 million square miles, is huge. It’s a continent, after all. For comparison, the continental United States is just 3.12 million square miles, Canada is 3.86 million square miles, and even Russia is only 6.6 million square miles. And Greenland? That hulking landmass hanging off Canada’s East coast is a comparatively tiny 836,300 square miles—roughly 14 times smaller than Africa.
The map above—the one you’re probably most familiar with—is called the Mercator projection. It’s an imperfect solution to a tricky problem. The Earth is roughly a sphere, whereas maps are flat. You can’t just peel the surface off a globe and lay it out: you have to use a mathematical projection to convert a 3D shape into a 2D one. In this case, it’s a cylindrical projection.
The Mercator projection is popular because it’s perfect for navigation. Any compass bearing is represented by a straight line, which historically meant sailors wouldn’t have to do loads of trigonometry or make frequent course corrections when sailing between two ports. It now means that GPS and online maps display roads’ directions accurately. The tradeoff is that the Mercator projection inflates the size of landmasses that are further from the equator. Greenland looks huge because it’s the most northerly landmass and so the most distorted, but every country not exactly on the equator is actually smaller than it looks on a Mercator projection map.
The problems with the Mercator projections have been known since it was created, and there are dozens of other projections with different characteristics. For example, equal-area projections, such as the pseudocylindrical Mollweide projection, preserve the relative size of things but distort their shape. Google Maps now uses a 3D globe when you zoom far enough out.
So, how do you actually compare the true size of different landmasses? One option is to go old school and grab a real globe. Remember, all the problems stem from projecting the surface of a 3D object onto a 2D map—the globe you had in your classroom was actually pretty accurate.
If you don’t have a globe handy, I love The True Size Of…. It’s a great webapp built on top of Google Maps. You’re able to select any country (or U.S. state), and drag it around a Mercator projection map so you can see what size it actually is, and compare it to any other landmass you want. Above, you can see the Continental United States, India, China, and tiny Ireland overlaid on top of Africa, as well as the still-large-but-now-much-smaller Greenland off to the side.