Flat Maps that improve on the Winkel Tripel

TL;DR

This paper introduces improved flat map projections of Earth and other celestial objects, achieving higher accuracy by minimizing error measures and proposing a novel double-sided map design.

Contribution

It presents a Gott-Wagner variant with better error scores and a new class of double-sided flat maps with vastly improved accuracy.

Findings

Gott-Wagner variant reduces error score from 4.563 to 4.497.

New double-sided maps achieve an error score of 0.881.

Maps of other solar system objects and sky maps demonstrate versatility.

Abstract

Goldberg & Gott (2008) developed six error measures to rate flat map projections on their verisimilitude to the sphere: Isotropy, Area, Flexion, Skewness, Distances, and Boundary Cuts. The first two depend on the metric of the projection, the next two on its first derivatives. By these criteria, the Winkel Tripel (used by National Geographic for world maps) was the best scoring of all the known projections with a sum of squares of the six errors of 4.563, normalized relative to the Equirectangular in each error term. We present here a useful Gott-Wagner variant with a slightly better error score of only 4.497. We also present a radically new class of flat double-sided maps (like phonograph records) which have correct topology and vastly improved error scores: 0.881 for the azimuthal equidistant version. We believe it is the most accurate flat map of Earth yet. We also show maps of other solar system objects and sky maps.