Re: Creating spatial indexes on geography slower than on geometry?
Paul Ramsey <[email protected]>
| Newsgroups | gmane.comp.gis.postgis |
|---|---|
| Message-ID | <[email protected]> |
Basically, yes. Calculating a bbox on a plane is just some min/max calls. Doing it on a sphere involves a lot of trig and huge functions. Calculating boxes is step one of index building. The geocentric geography index involves a varsize key, while the 2d geometry index uses a fixed size key. Even things like distance cost a lot more https://docs.google.com/presentation/d/1G7UkT9szpyRcWPp59aVRfN1-f1jfuf40dwxs034M2RA/edit#slide=id.g4c694067b3_0_79 p > On Nov 1, 2024, at 8:13 AM, [email protected] wrote: > > Is that because geometry is calculated in the plane whereas geography on a curved surface? > > Paul Ramsey <[email protected]> escribió: > >> Yes, building a geography index is a lot more computationally expensive. > >