[postgis-users] coordinate reference system

[François Dubreil]

Hi all

I'd like to use some CRS, which srid in the EPSG database are 2154 (RGF 93 / 
Lambert-93) and 27572 (seems like Lambert 2 etendu). But they're not in the 
spatial_ref_sys table of my postgis database (and not, of course, in the 
spatial_ref_sys.sql file). Besides the parameters used for another crs 
(srid=27582) are a little bit different in the EPSG database and in the 
spatial_ref_sys table.

So, I have a few questions about CRS and postgis.

What is the source of the data used for building the spatial_ref_sys sql 
script ?
I saw in the mail-archive a thread about creating our own CRS. Is it the way I 
should operate ? Is there an update of the spatial_ref_sys table in the 
project plans ?

Thanks
François