It turns out that another projection — the azimuthal equidistant projection – provides exactly what we want: It measures distance accurately from the center of the map.

By their calculations, the Mercator projection scores 8.296 and Winkel Tripel does better at 4.563. Their own azimuthal equidistant double-sided projection, meanwhile, scores 0.881.

The azimuthal orthographic is thousands of years old. In the first century, Ptolemy described how a geographer named Hipparchus used the projection, which he called the analemma, to map the globe.

Rogerson’s technique uses what geographers call an azimuthal equidistant map projection, which preserves important qualities related to distance when a rounded 3-D portion of the Earth is projected as ...