On 3/24/2010 1:29 AM, Mike Toews wrote:
Hi Paul,
To get the bounds for one layer/table, you need an aggregate
(ST_Collect) and envelope on the aggregate. For one layer/table, it
would look something like:
SELECT ST_AsText(ST_Envelope(ST_Collect(the_geom))) AS envelope FROM mylayer;
Sorry, Mike, but I don't think you want to do this.
As an example, I have a linear table of 18 million records spanning about 12GB of data. Your solution will try to
create a single geometry from the entire collection (a single 12GB geometry object) and then take the envelope of it.
Rather, as Debasish Sahu suggested, use ST_Extent
(http://postgis.refractions.net/docs/ST_Extent.html).
Cheers,
Kevin
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