[postgis-users] Transform Coordinates

[Jean David TECHER]

The two options are right but becarefull with the second!

You will have to do something like

ALTER TABLE ADD COLUMN ...

Because of  the remarks taken from PostgreSQL doc

"Adding a column with a non-null default or changing the type of an  
existing column will require the entire table to be rewritten. This  
may take a significant amount of time for a large table; and it will  
temporarily require double the disk space."

So check that's you have enough space if your table is very big

Please see http://www.postgresql.org/docs/8.X/static/sql-altertable.html

where X=0,1,2,3

--david;




Quoting Nicolas Ribot <nicky666 at gmail.com>:

>> How can I transform the coordinate system of a table ?
>> I know the SRID is 4326.
>>
>> Thanks a lot
>>
>
> Basically, by using st_transform(geometry, srid) on your table.
> It may be a little more complicated if you have SRID constraints on   
> your table.
>
> 2 options among several:
>
> 1°) Drop the constraint, update your data by transforming them, readd
> the constraint with updated SRID value
>
> 2°) Add a new geometric column to your table and insert into it
> transformed geometries from the first column.
>
> HTH
> Nicolas
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>



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Jean David TECHER
www.davidgis.fr
06 60 46 85 05
04 99 77 16 87
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