[postgis-users] Transform Coordinates

[lisek lichu]

WOW i didn't know that

Thanks a lot :P

On Wed, Nov 12, 2008 at 18:16, Jean David TECHER
<david.techer at davidgis.fr>wrote:

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