Arthur Robinson, the cartographer and geographer best known for his elegant solution to a mapmaking conundrum, died last October 10 at the age of 89. He merged a sense of aesthetic clarity with the mathematical rigor of science to reimagine the Mercator projection, a method for representing the round earth on a flat surface that had prevailed for the better part of four centuries.

In 1569, the Flemish cartographer Gerardus Mercator created a map of the world on a flat surface, as opposed to a globe. Such a map would be particularly useful for sailors. In doing so, however, Mercator encountered a challenge that was as old as the craft of mapmaking itself: how can a curved surface be accurately represented on a flat plane?