Map Projection Cartoon

Mercator ProjectionIf you read this whole article, I will reward you with a cartoon. But I know what you’re thinking, “I can just skip down to the cartoon and read it now!” Silly reader! You won’t be able to understand it without reading this article. Unless you know a lot about map projections. You don’t, do you? I’ll bet you don’t know anything, and now that I’ve turned off comments, I don’t even have to risk hearing that I’m wrong!

Projection Wars

Imagine that you are part of a group that works for pedestrian rights. For years, you’ve been lobbying the government to get rid of the “right turn on red light” law because it is so dangerous for pedestrians. Then this guy, who has no connection with your group, holds a press conference. He says, “This ‘right turn on a red light’ is madness! It must be changed. All these pedestrian rights people are wrong for supporting this law all these years.” You’d be pissed off at the guy, right?

That’s what happened in 1973, when Arno Peters held a press conference to blast the cartography profession and propose his new projection. But I’m getting ahead of myself.

Map Projections

The world is spherical—or very nearly: it is wider in the middle than from top to bottom, just like many people my age. Maps are flat, and despite what the flat earth society might tell you (there really is one), the earth is not. So in order to translate the 3D globe onto a 2D page, compromises must be made.

There are hundreds of different map projections. Wikipedia lists almost 100 specifically. Why? Because each one has its advantages. For example, the Mercator projection (the one you probably think of when you think of a world map) is great for use in navigation. But it is horrible to look at; it greatly distorts the sizes of different places; for example, Greenland is as large as Africa, even though Africa is 14 times as big.

Back to Arno Peters

Arno Peters made a big splash in the 1970s when he came out with his map. It turned out it wasn’t new; James Gall had invented it 120 years earlier, but Peters probably didn’t know about it. What was important was not the details of the map, but why Peters thought a new map was needed.

Peters felt that the Mercator projection had bad political implications. And he was right. Just look at it: the countries surrounding the equator are minimized. Peters map does indeed fix this problem. But he made a lot of other claims for the map that turned out to be false, probably because he was not a cartographer.

The cartography community had long been complaining that the Mercator map was a lousy choice for general-purpose. They attacked back and forth and now, among many people, Peters and his map are vilified. This is wrong, I think. The truth is that Peters was able to do what the cartography community had not been able to do in 400 years: get non-cartographers to care about this issue.

The main problem with the Gall-Peters projection is that it looks kind of odd. The areas may be right, but the shapes are wrong. There are other maps that do the same thing better.

Other Projections

Back in about 100 AD, Marinus of Tyre came up with the projection I would have: meridians become equally spaced up and down lines; circles of latitude become equally spaced right and left lines. It is called the equirectangular or the plate carrée (square plate) projection. Sure, it is not accurate, but it’s easy and it looks pretty good.

The Walter Behrmann projection is really great. It does what the Marinus of Tyre projection does with the meridians, but it squishes the circles of latitude as they get away from the equator. In 2002, the Hobo-Dyer projection was developed based upon the Behrmann projection. How they are different, I don’t know, because I just don’t care that much.

There are, as I’ve noted, lots of other projections. And they all have their uses, even the weird ones, like the Waterman butterfly. (But don’t let the cartoon fool you, the Hobo-Dyer is a lot more recent.)

Randall Munroe Cartoon

Now you know enough to appreciate one of Randall Munroe’s more obscure cartoons—and that’s saying something.

Map Projection Cartoon

One reply

  1. […] has behind him. I like maps. I like how they distort reality. So it is nice to be reminded with different projections and different orientations. But if you are going to have a south side up map in back of you, you […]

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