[postgis-users] ST_Union on empty polygon loses SRID

[Jonathan Schultz]

This is actually in response to Regina Obe's email which I didn't 
receive but only saw on the list archives. Maybe there is another way of 
replying to her message but I don't know it.

I have definitely upgraded my debian/unstable installation.

 > $ dpkg-query -W postgis
 > postgis 3.1.4+dfsg-3+b1

but still I get the previously mentioned response to postgis_full_version()

I had presumed that this was just due to debian and postgis maintaining 
different versioning systems. But is it possible that postgresql is for 
some reason not registering the upgrade to postgis?

One possibly related problem I found was:

> SELECT postgis_extensions_upgrade();
> NOTICE:  Updating extension postgis from 3.0.2 to 3.1.0alpha1
> ERROR:  extension "postgis" has no update path from version "3.0.2" to version "3.1.0alpha1"
> CONTEXT:  SQL statement "ALTER EXTENSION postgis UPDATE TO "3.1.0alpha1";"
> PL/pgSQL function postgis_extensions_upgrade() line 68 at EXECUTE

Any suggestions?

Thanks!


On 27/11/21 15:18, Darafei "Komяpa" Praliaskouski wrote:
> Does not reproduce on my 3.2 and 3.1.4 installs:
> 
> 10:17:37[gis] > select postgis_full_version();
> ┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ 
> 
> │ 
>                                                                                                                       postgis_full_version                                                                                                                       │
> ├─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤ 
> 
> │ POSTGIS="3.2.0dev 3.2.0beta1-23-g94d4588ac" [EXTENSION] PGSQL="140" 
> GEOS="3.10.0dev-CAPI-1.15.0" SFCGAL="1.3.8" PROJ="7.2.1" GDAL="GDAL 
> 3.2.2, released 2021/03/05" LIBXML="2.9.12" LIBJSON="0.15" 
> LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)" TOPOLOGY RASTER │
> └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ 
> 
> (1 row)
> 
> Time: 47,743 ms
> 10:17:43[gis] > select ST_SRID(ST_Union(ST_GeomFromText('POLYGON EMPTY', 
> 4283)));
> ┌─────────┐
> │ st_srid │
> ├─────────┤
> │    4283 │
> └─────────┘
> (1 row)
> 
> Time: 1,531 ms
> 
> 
> On Sat, Nov 27, 2021 at 7:34 AM Jonathan Schultz <jonathan at schultz.la 
> <mailto:jonathan at schultz.la>> wrote:
> 
>     Hello,
> 
>     I have found with a query that makes a union of geometries which
>     includes an empty polygon produces a result without an SRID. For a
>     trivial example:
> 
>       > => select ST_SRID(ST_Union(ST_GeomFromText('POLYGON EMPTY', 4283)));
>       >  st_srid ---------
>       >        0
> 
>     This seems like a bug to me but maybe there is a good explanation?
> 
>     Thanks,
>     Jonathan
>     _______________________________________________
>     postgis-users mailing list
>     postgis-users at lists.osgeo.org <mailto:postgis-users at lists.osgeo.org>
>     https://lists.osgeo.org/mailman/listinfo/postgis-users
>     <https://lists.osgeo.org/mailman/listinfo/postgis-users>
>