Why maps lie

Every flat map of the world is wrong. This is not carelessness; it is geometry. A sphere cannot be flattened without stretching something, so every map chooses what to distort.

The Mercator projection, familiar from classroom walls, keeps angles correct, which made it valuable for navigation: a straight line on the map is a constant compass bearing. The cost is area. Greenland appears roughly the size of Africa, although Africa is about fourteen times larger. Countries near the equator — most of Africa, India, Indonesia, Brazil — look smaller than they are, and countries far from it look larger.

Other projections make other trades. Equal-area maps keep sizes honest and bend shapes instead, which looks strange to eyes trained on Mercator. Some projections cut the oceans into pieces so that continents keep both shape and size; they are accurate and useless for showing a sea route.

The general lesson is more useful than the particular maps. Any representation of something complicated throws information away, and the choice of what to throw away reflects a purpose. A league table, a chart of weekly minutes and a single average score are all projections of a class, and each hides something. Asking what a picture distorts is not scepticism for its own sake; it is how you find out what it was made for.