Re: [postgis-users] point_ops with GiST PostGIS Spatial Index - Mailing list pgsql-general
From | BladeOfLight16 |
---|---|
Subject | Re: [postgis-users] point_ops with GiST PostGIS Spatial Index |
Date | |
Msg-id | CA+=1U=WqDyXp+-tj5+V4dGx7ZE5Eu20b2jVD8jmLRGQ=FeyTSw@mail.gmail.com Whole thread Raw |
In response to | Re: [postgis-users] point_ops with GiST PostGIS Spatial Index ("Tambade, Kedar" <ktambade@cghtech.com>) |
List | pgsql-general |
So when that index is created, is PostgreSQL/PostGIS somehow figuring out that my geometry consists of points only and using the point_ops operator class, or is it just using the operator class that goes with && (bounding box overlap operator), or are those operators in the same class? I'm pretty much lost on which operators and indexes go with what classes. (point_ops is the only operator class I've even heard of.)
Thanks again.
Create the gist index on table containing points using the following syntax:
CREATE INDEX <index name> ON <table name> USING GIST (<geometry column name>);
After the index is created use the criteria st_contains(polygon,point) in the where clause of select statement:
Select * from <tablename> where st_contains(polygon, point) ;
Regards,
Kedar Tambade
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From: postgis-users-bounces@lists.osgeo.org [mailto:postgis-users-bounces@lists.osgeo.org] On Behalf Of BladeOfLight16
Sent: Wednesday, June 05, 2013 2:29 PM
To: PostGIS Users Discussion; pgsql-general@postgresql.org
Subject: [postgis-users] point_ops with GiST PostGIS Spatial Index
I posted this question on StackOverflow, and the only person to answer recommended I ask these lists for more details and link to the question:
http://stackoverflow.com/questions/16927331/postgresql-point-ops-with-gist-postgis-spatial-index
My question is:
The 9.0 release notes for PostgreSQL states the following change:Add point_ops operator class for GiST (Teodor Sigaev)
This feature permits GiST indexing of point columns. The index can be used for several types of queries such as
point <@ polygon
(point is in polygon). This should make many PostGIS queries faster.I have a very large table (millions of rows) with a
GEOMETRY(POINT,[SRID])
column that I sometimes compare to polygons. Do I need to do anything to enable this when creating the index? Do I have to use the operator indicated, or would this work withST_Contains
which uses&&
internally?Thanks for any help.
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