[postgis-users] several SRID on one table

[Steve.Toutant at inspq.qc.ca]

Thanks Pavel for your answer.
Do you suggest that I could use one geometry column and create several 
index instead?

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
 




Pavel Iacovlev <iacovlev.pavel at gmail.com>@postgis.refractions.net 
Envoyé par : postgis-users-bounces at postgis.refractions.net
01/09/2009 11:34 AM
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Re: [postgis-users] several SRID on one table








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
>
>
>
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>
>



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