On Sep 3, 12:55 pm, John Poole <[email protected]> wrote: > I have a table of assessor parcels (polygons) and I want to take a > given point (actually will be taking samplings from a geocache > tracker, so I'll be doing hundreds, possibly thousands of such > queries) and determine which, if any, of the shapes contain the point. > The goal is to determine which parcel a tracked person is within and > at what times. > > I'm new to spatial database, and suspect performing a relate or > ST_contains against the 40,000 shapes would be horribly inefficient, > especially if I have thousands of points. Should I be reading up on > indexes, or is there an elegant solution to this problem. > > I tried searching the archive of this list for "point in field of > shapes" but results were too generic. > > John L. Poole
That shouldn't be very taxing. A bounding box check in the where clause should help speed things up. e.g. select p.id from parcels p left join geocache g on st_contains(p.geom, g.geom) where p.geom && g.geom You'll only really know how efficient it is when you try it with real data. Of course, make sure you have a spatial index on the polygons. Sean _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
