[postgis-users] several SRID on one table

[Pavel Iacovlev]

Depends on your update/select ratio. If you have lots of SELECT like
90% and few updates and your just serving your data lets say to
mapserver I would just go with 2 geometry columns iit's easier and
faster.

On Tue, Sep 1, 2009 at 6:39 PM, <Steve.Toutant at inspq.qc.ca> wrote:
>
> 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
>
> Veuillez répondre à
> PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> A
> PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> cc
> Objet
> 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
>>
>>
>>
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