LAST month Kai Krause, a computer-graphics guru, caused a stir with a map entitled “The True Size of Africa”, which showed the outlines of other countries crammed into the outline of the African continent. His aim was to make “a small contribution in the fight against rampant Immappancy”—in particular, the fact that most people do not realise how much the ubiquitous Mercator projection distorts the relative sizes of countries.

A sphere cannot be represented on a flat plane without distortion, which means all map projections distort in one way or another. Some projections show areas accurately but distort distances or scales, for example; others preserve the shapes of countries but misrepresent their areas. You can read all the gory details on Wikipedia.