If you like this stuff, have a look at Healpix: http://healpix.sourceforge.net/ http://healpix.sourceforge.net/ It splits sphere into pixels each with separate

If you like this stuff, have a look at Healpix: http://healpix.sourceforge.net/ http://healpix.sourceforge.net/ It splits sphere into pixels each with separate number. It is sort of fast hashing for spherical purposes in astronomy. It does not require trigonometric operations and is very fast.