I really like how fast it is. For example irregular area size of Greenland at 1 meter accuracy only takes a few hundred MB. One can do joins and unions, on such areas on modest laptop.
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 :-)
I really like how fast it is. For example irregular area size of Greenland at 1 meter accuracy only takes a few hundred MB. One can do joins and unions, on such areas on modest laptop.
Disclaimer: I send a few patches to this project.