[postgis-users] ¿obtain the bounding box from grup of poligon?

[Nicolas Ribot]

On 18 August 2010 21:05, salas <fsalas at geocuba.cu> wrote:
> Hi, i have the parcels table , and select various polygon
>
> ¿ how i can obtain the boundary of this group?
>
> best regards, salas
>

Hi,

Or using the st_extent aggregate function
(http://postgis.refractions.net/docs/reference.html), eventually with
the group by operator to isolate sets of polygons.

Performing a union on the geometries to extract the bouding box may
take a lot of time.

Nicolas