[postgis-users] update / closest polygon
josh at livniconsulting.com
Fri Mar 3 09:09:52 PST 2006
I have a basic 'update' question. For a simple example, given a bunch
of points, I'd like to give them attributes based on the closest polygon.
Let's say I try this:
SET p_distance = distance(centroids.the_geom, polygons.the_geom),
WHERE expand(centroids.the_geom,1000) && polygons.the_geom
and Distance(centroids.the_geom, polygons.the_geom) < 1000
This associates any polygon within 1k to the point -- but not
necessarily the closest. Is there an easy way to bring in an 'order by
distance' and 'limit 1' kind of idea to the UPDATE query? Do I need to
do that in a separate select, make a temp table, and then join?
Thanks in advance for any pointers.
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