[postgis-users] PostGIS Transform and Quantum GIS

[Paul Ramsey]

Try removing the table from qgis and re-adding it. And don't forget to
change the SRID value in GEOMETRY_COLUMNS before you do. I think
you're altering the coordinates underneath QGIS's understanding of
that they are (it things it has a 4326 table, and boom, you turn it
into something else).

P.

On Fri, Oct 10, 2008 at 7:16 AM,  <cyw at dls.net> wrote:
> Just wonder if anyone had similar experience.
>
> I have a table with multipolygons for cities (in latitude/longitude,
> srid=4326), I could display it with QuantumGIS.
>
> Then I did a transform to a plane coordinate system, and verified the result
> (astext(the_geom)) and saw  no problem.
>
> Then I tried to view it again with QuantumGIS. Though no error message,
> nothing could be display. After zoom-to-layer, the cursor coordinate values
> were consitent with the extent of the data in the projected coordinate
> system.
>
> Below are the SQL command I did:
>
> ALTER TABLE city DROP CONSTRAINT enforce_srid_the_geom;
> update city set the_geom=transform(the_geom,26971)  where
> polygon_id=35665106;
> alter table city add CONSTRAINT enforce_srid_the_geom CHECK (srid(the_geom)
> = 26971);
>
> Thanks,
> CYW
>
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