[postgis-users] several SRID on one table

[Pavel Iacovlev]

The cons I think are that some 3rd party apps may get confused then
working with PostGIS as they expect 1 geometry column per table, old
version of QGIS have this problem (I may be wrong).

In general you should have NO trouble with dual geometry columns in
your app, I use this approach in production and it works fine and it's
easy to implement.

As a note you can create an INDEX on a geometry column that is a
transformed geometry to specified projection and you should get really
fast geometry on the fly projection transformation.
CREATE INDEX myindex ON mytable USING GIST ( ST_Transform(the_geom, mysrid) );
Don't  forget to run EXPLAINS to see if it actually works.

On Tue, Sep 1, 2009 at 5:46 PM, <Steve.Toutant at inspq.qc.ca> wrote:
>
> Hello,
> We need to use a table for several purposes with different SRID.
> Is it a good practice to have several geometry columns on one table or
> should we create one table per SRID?
> What are the pros and cons of using several geometry columns on one table?
>
> thanks
> Steve
>
> Steve Toutant, M. Sc.
> Analyste en géomatique
> Secteur environnement
> Direction des risques biologiques, environnementaux et occupationnels
> Institut national de santé publique du Québec
> 945, avenue Wolfe
> Québec, Qc G1V 5B3
>
> Tél.: (418) 650-5115 #5281
> Fax.: (418) 654-3144
> steve.toutant at inspq.qc.ca
> http://www.inspq.qc.ca
>
>
>
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