Re: contains function

Thank you very much. I just subscribed to the postgis-users mailing list
yesterday and will take another look at the postgis documentation. Knowing
the difference between the polygon and the geometry is definitely going to
help. Thank you.

Frances Collier


-----Original Message-----
From: pgsql-novice-owner@postgresql.org
[mailto:pgsql-novice-owner@postgresql.org] On Behalf Of Michael Fuhr
Sent: Wednesday, October 05, 2005 10:11 PM
To: Frances Collier
Cc: pgsql-novice@postgresql.org
Subject: Re: [NOVICE] contains function

On Wed, Oct 05, 2005 at 01:06:37PM -0700, Frances Collier wrote:
> Are there any examples of using postgis that I can use for research?

Consider subscribing to the postgis-users mailing list if you're
using PostGIS:

http://postgis.refractions.net/support/

> Select astext(wkb_geometry), name, state
> From usroads
> Where state = 'Alabama'
> And name like '%Ross Clark%'
> And Contains(polygon('(-85.440253,31.207678),(-85.421703,31.207678),
> (-85.421703,31.226228),(-85.440253,31.226228),
>                                  (-85.440253,31.207678)'), wkb_geometry);
> 
> Here is the error I'm getting back:
> 
> ERROR:  function contains(polygon, geometry) does not exist
> HINT:  No function matches the given name and argument types. You may need
> to add explicit type casts.

You're mixing a PostgreSQL polygon type and a PostGIS geometry type;
the Contains() function takes two geometry types.  Use a constructor
like GeomFromText() or PolyFromText() to build the polygon.  See
"Using PostGIS" in the PostGIS documentation for examples:

http://postgis.refractions.net/docs/

Be sure to read "Taking Advantage of Indexes" to understand how to
speed up queries such as the above with bounding box searches.

-- 
Michael Fuhr

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