[postgis-users] st_within too slow?

Obe, Regina robe.dnd at cityofboston.gov
Sat Aug 30 05:59:34 PDT 2008


Try using st_intersects instead of ST_within.  In general I think it performs better than within and for point in poly will be just as good.

Yah Guido's suggestion would be at best give same timing since ST_Within, ST_Intersects have an implicit && call in them so they can limit the number of more painful _ST_Within, _ST_Intersects checks they actually need to do.

Hope that helps,

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net on behalf of Pedro Doria Meunier
Sent: Sat 8/30/2008 8:16 AM
To: PostGIS Users Discussion
Subject: RE: [postgis-users] st_within too slow?
Dear Guido,

Thanks for replying.
Your suggested mod actually worsens the performance by another ~15-20ms

Best regards,
Pedro Doria Meunier <pdoria at netmadeira.com>

> Pedro,
> Try this instead:
> SELECT road_network, toponymy FROM maps AS m WHERE m.b_box &&
> geomfromtext('POINT($lon $lat)',4326) and
> st_within(geomfromtext('POINT($lon $lat)',4326), m.b_box)
> of course, if you already know that the point is in Portugal,
> you could do:
> SELECT road_network, toponymy FROM maps AS m WHERE 
> m.country = 'PT' and 
> m.b_box && geomfromtext('POINT($lon $lat)',4326)
> (assuming that the maps table has the 'country' column with
> country names).
> GL

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