HEALpix is cool. It has the same connectivity issue as with all the solutions — some locations are a little different. With hexagons a few polygons are differen

HEALpix is cool. It has the same connectivity issue as with all the solutions — some locations are a little different. With hexagons a few polygons are different (polygons); with HEALpix a few vertices are different (three quads instead of four). In games we can get away with not mapping everywhere whereas in astronomy we can't :-)