Fun with map projections.

Here's something you might not know about me: I love maps. Love 'em. And map projection is really super fascinating. I mean, think about it: The earth is sphere, and not even close to a perfect one, and yet we are all more familiar with the way it looks flattened out. But how do you flatten out a sphere?

Welcome to the wonderful world of map projection.

This is Ptolemy's map of the world, created in the 2nd century, C.E. Since Ptolemy was not an idiot, he knew that the earth was round and his map sort of reflects that knowledge, though I'm not sure what the deal is with the cherub things around the map's perimeter. However, Europe and Western Asia are recognizable.

The most interesting thing about this map though, is that big island in the lower, right half. Any guesses what that is? It's Sri Lanka. But wait, you say -- Sri Lanka is not bigger than Spain! And where's India? Fair points. India is that tiny little pointy thing north of Sri Lanka. But -- but -- India is so much bigger than Sri Lanka! Well, yeah. It is. So why did the map end up being this way?

Welcome to map distortion, my friends, the evil twin of map projection. You can't have one without the other. 

(I just realized I'm being shamefully nerdy about maps. Eh.)

The reason why Sri Lanka ended up being so inaccurately large has to do with the island's importance to European traders. Sri Lanka, or Ceylon back then, was a huge center of trade in the Indian Ocean. It's importance and prominence translated into square mileage on Ptolemy's map. Whereas India, not such a big deal back then, doesn't even really make an appearance.

Well, you say, that is ridiculous! Thank God we have accurate maps nowadays! 

I smile with delight at your ignorance and prepare to educate you on the problems with modern map projections.

Let's look at the two map projections discussed in this great clip from The West Wing, and then explore less familiar and newer projections.

The Mercator Projection:

This projection looks nice to us, probably because it's the most familiar. It's the one used on Google Maps. All map projections strike a balance of accuracy in size and accuracy in shape. The Mercator Projection picks shape over size, all the way. As demonstrated in the West Wing clip, Greenland, while appearing monstrous, is actually this size, comparatively to Africa:

What's more disturbing, though, than making a glacier where no one lives look bigger than it actually is, is making a huge, diverse continent where 1 billion people live look much smaller than it actually is. Thanks, Mercator projection. This is a picture I want everyone to see and, like, hang on their wall and just let it sink in: 

Africa, I appreciate how large you are.

Another smaller, more personal gripe about the Mercator projection: I was led to believe than Norway, Sweden and Finland are actually fairly large countries! They are not. My score on Sporcle quizzes has suffered in result. See, map projections have real world consequences.

The Peters Projection:

The Peters Projection picked size over shape. I see and appreciate their cause, but actually now Canada and Russia look like they're not the biggest two countries in the world, so that's no good. Plus this map is not nice to look at. Africa looks great, though. But everything around the poles got all squatty and ugly looking. It makes people accustomed to the Mercator Projection (which is everyone) uncomfortable. And maps should be fun to look at. Nice try, Peters Projection, but this isn't a solution. What we need is a compromise between size and shape.

Robinson Projection:

This compromise projection looks great (excepting Antarctica) and strikes a nice balance between accuracy of size and shape.

Cahill Butterfly Map:

Interesting, but kind of disorienting.

Goode Homolosine Projection:

Similar to the butterfly map, while preserving north-south orientation. Generally nicer to look at, but still sort of funky.

Mollweide Projection:

This is a very nice map, and Antarctica has been reined in a little. Always appreciated.

Werner Projection:

This heart-shaped projection is great for looking at the north pole, but not so great for much else. Like, check out Australia. What's up with Australia?! 

There will be distortion in maps for as long as we insist on projecting a sphere's surface onto a two-dimensional piece of paper. There's no totally satisfying solution, so the answer is to use a variety of maps and understand that none are perfect. And use globes whenever possible. Globes are fantastic.