[postgis-users] Help shaping the future: how do your use of spatial_ref_sys ?

Paul Ramsey pramsey at cleverelephant.ca
Tue Feb 8 14:44:49 PST 2022

On Fri, Feb 4, 2022 at 2:23 PM Jim Klassen <klassen.js at gmail.com> wrote:

> We've been starting at 200000 and using EPSG (misusing the "EPSG" auth kept Proj 4/GDAL/MapServer happier, this likely isn't necessary with Proj 8).  We maintain matching record(s) in our proj4 epsg database file (again this will change as we transition to Proj 8 which supports PROJ_AUX_DB).

Slightly off topic, but a note to your and Paul Moen, that putting
"EPSG" into the auth_name means that in dereferencing the spatial
reference info PostGIS ends up calling into proj and saying "is this
bogus projection EPSG:9999999 projection valid?" which takes time.
Whereas if auth_name is null, PostGIS just skips right on down to
using the WKT. And if *that* is null, it can skip directly to using
the proj4text. So if you're really only using the proj4text, it
behooves you to leave everything else null.

It's probably only a very tiny efficiency, since after the lookup
everything is cached anyways, but I thought I'd lay it out there.


More information about the postgis-users mailing list