WKT2 in PostGIS

[Paul Ramsey]

Why wouldn’t we just change those column definitions from varchar(N) to text? 

> On Sep 9, 2026, at 8:47 AM, Regina Obe <lr at pcorp.us> wrote:
> 
> Javier,
>  
> We’ve been hesitant to touch this table to increase it. I know someone else requested this.
> Our feeling is the proj.db should be the authoritative source for most of these.
>  
> I there a reason you wouldn’t add this to proj directly?  The issue with putting it in postgis spatial_ref_sys is if you use your system beyond postgis
> You’d have to duplicate the entry anyway.
>  
> But I am and I think others were concerned for many users especially those who don’t need these defs elsewhere, it’s easier to edit postgis.spatial_ref_sys,
>  
> PostGIS for since I think 3.0 has delegated most stuff to the proj.db table and just uses spatial_ref_sys auth_srid to look up the record in proj.db and largely ignores what is in srtext/proj4text columns.
>  
> I have to check the auth_name.  I think we used to ignore what was in auth_name and assumed any auth_srid matched up with auth_name = epsg, but that I think changed somewhere across the line.
>  
> Paul,
>  
> If per chance you have remember or have the energy to chime in on this, that would be much appreciated.
>  
> Thanks,
> Regina
>  
> From: Javier Jimenez Shaw <j1 at jimenezshaw.com> 
> Sent: Wednesday, September 9, 2026 7:09 AM
> To: postgis-devel at lists.osgeo.org
> Subject: WKT2 in PostGIS
>  
> Hi
> 
> In the new PROJ release 9.9.0 that will be released soon, the latest version of EPSG is included.
> All European realizations are included in the WKT2 of any CRS using the ETRS89 datum ensemble.
> This is an example of EPSG:25830, with 4264 chars.
>  https://epsg.org/crs/wkt/id/25830
> If you format it a bit nicely it goes up to 4874. And this is just an example.
>  
> I know that this one can be expressed just with the code. However some people (including me) need to define a CRS that is not defined in EPSG. For that we are using WKT2.
>  
> I realized today that in PostGIS the table containing the CRS has fields limited to 2048 chars, in particular "srtext".
> https://postgis.net/docs/using_postgis_dbmanagement.html#spatial_ref_sys_table
> 
> CREATE TABLE spatial_ref_sys (
>   srid       INTEGER NOT NULL PRIMARY KEY,
>   auth_name  VARCHAR(256),
>   auth_srid  INTEGER,
>   srtext     VARCHAR(2048),
>   proj4text  VARCHAR(2048)
> )
> 
> If I have to define a CRS with WKT2 because I need some features only available in WKT2, it may not work in PostGIS. Am I right?
> 
> Thank you.
> Javier.
>  
> PS this was first asked in https://lists.osgeo.org/pipermail/proj/2026-September/012183.html

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