H3C: a PostgreSQL library to deal with positions

H3C (HEALPix-Tree -C) is a PostgreSQL library which contains functions to index positions (ra,de) with HEALPix and others usefull functions like cone search, crossmatch, etc.

H3C is largely inspired from Q3C which is based on Qbox. The functions are similar in name and in functionnalities in the both library (except the prefix name and the Polygons functions limited for convex only in H3C).

H3C uses the HEALPix library maintained by the Nasa. For efficiency, get the last 64bits version of the library using this link.

Depending of the PostgreSQL installation, H3C needs an appropriate tuning. see H3C tuning.