The OGC definition for Contains and Within have always seemed a bit
non-intuitive to me. They may be theoretically elegant. but they don't
really address the most common use case. (See a blog post on this as:
http://lin-ear-th-inking.blogspot.com/2007/06/subtleties-of-ogc-covers-spatial.html).
That's why JTS, GEOS and PostGIS define the covers() predicate, which
has simpler, more intuitive and more practical semantics.
http://postgis.refractions.net/documentation/manual-1.4/ST_Covers.html
Luigi Castro Cardeles wrote:
Hi list and Chris,
this is what i was asking :D
i was thinking that boundary is part of the geometry, so if there is
some geometry on the boundary (in this case, a point on the polygon
boundary) then the point is within the polygon. But after your message
i read the specs
(http://portal.opengeospatial.org/files/?artifact_id=18241) about
within, i see the relate and now i understand. Thanks for the hint Chris.
[]'s
Luigi Castro Cardeles
2009/9/18 Chris Hermansen <[email protected]
<mailto:[email protected]>>
If it's on the boundary, is it within?
Chris Hermansen [email protected]
<mailto:[email protected]>
tel+1.604.714.2878 · fax+1.604.733.0631 · mob+1.778.840.4625
Timberline Natural Resource Group · www.timberline.ca
<http://www.timberline.ca>
401 · 958 West 8th Avenue · Vancouver BC · Canada · V5Z 1E5
-----Original Message-----
From: Luigi Castro Cardeles <[email protected]
<mailto:[email protected]>>
Date: Fri, 18 Sep 2009 10:01:32
To: PostGIS Users Discussion<[email protected]
<mailto:[email protected]>>
Subject: Re: [postgis-users] Problem with ST_WITHIN
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