HEALPix

[1] The pixelisation algorithm was devised in 1997 by Krzysztof M. Górski at the Theoretical Astrophysics Center in Copenhagen, Denmark,[2] and first published as a preprint in 1998.

The scheme has a number of mathematical properties which make it efficient for certain computations, e.g. spherical harmonic transforms.

The pixelisation related to the H=4, K=3 projection has become widely used in cosmology for storing and manipulating maps of the cosmic microwave background.

The scheme is good at representing complex shapes because the boundaries are all segments of circles of the sphere.

The 12 "base resolution pixels" of H=4, K=3 HEALPix projection may be thought of as the facets of a rhombic dodecahedron.

HEALPix H=4, K=3 projection of the world. The lines on the map are a graticule of latitudes and longitudes.
The grid used by HEALPix and its subdivision of the sphere, in four different grid refinements. Notice the similarity between the coarsest grid and the rhombic dodecahedron .