[postgis-devel] Motion: vote for considering SRID <= 0 as "unknown"

Mark Cave-Ayland mark.cave-ayland at siriusit.co.uk
Tue Oct 4 07:54:28 PDT 2011

On 04/10/11 14:56, Sandro Santilli wrote:

> Trying to get out of the impass about SRID, I'd like to split
> the issue in two:
>   (1) Considering SRID<= 0 as "unkwnown"
>   (2) Finding a consensus about how to advertise "unknown"
>       at the SQL level
> I'd like to vote on (1) first.
> If we agree, the parsers (all of them) would take any SRID<= 0 as
> semantically equivalent to an "unknown SRID", storing NO srid in
> the binary representation.
> This would mean that no matter what we decide to return from ST_SRID(g)
> it will be possible to get in output something different from what was
> specified in input.
> I'll start with my +1.

My only comment would be what do the various standards (SQL-MM/OGC) say 
about SRID values? As long as they don't specify anything, I guess we 
have a bit more freedom to interpret the specification as fits best with 



Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
t: +44 870 608 0063

Sirius Labs: http://www.siriusit.co.uk/labs

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