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

Sandro Santilli strk at keybit.net
Thu Oct 6 02:43:30 PDT 2011

On Wed, Oct 05, 2011 at 11:14:35AM -0700, Paul Ramsey wrote:
> +1 for "srid <= 0 implies unknown"

Great. 4/5 +1s. Mark still missing.

Meanwhile my patch is being tested and just as soon as I tried approaching
ST_Srid I hit the _Best_SRID issue. That function uses a negative SRID
to signal something to the ST_Transform function. Maybe it has to do 
with the proj4 cache, I dunno.

Paul: could you take a look at that to make sure not to rely on any
non-unknown negative srid at the SQL level ?

To be clearer, this is the problem at the SQL level:

=# SELECT ST_Intersection(ST_GeographyFromText('POINT(0 0)'), ST_GeographyFromText('POINT(0 0)'));
ERROR:  Input geometry has unknown (0) SRID

Which I belive happens due to:

=# select _ST_BestSRID('POINT(0 0)', 'POINT(0 0)');
(1 row)


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