Hi list and Martin, many thanks :D
[]'s Luigi Castro Cardeles 2009/9/21 Martin Davis <[email protected]> > Switch the arguments around. > ST_covers(A, B) = true iff A covers B > In other words, ST_covers(LINE, POLYGON) = false, but ST_covers(POLYGON, > LINE) = true. > > In other other words, the order of the arguments for ST_covers should be > the same as for ST_within, and opposite to ST_contains > > Luigi Castro Cardeles wrote: > >> Hi list and Martin, >> >> If i use st_covers, the query 1 and 2 return's false. >> After read the blog, i am thinking that covers should return true at that >> cases. >> query 1: >> select ST_covers >> ( >> geomfromtext('LINESTRING(10 18, 30 18)',4326), >> geomfromtext('MULTIPOLYGON (((10 18,30 18,30 12,10 12,10 >> 18)))',4326) >> ) >> >> and >> >> query 2: >> select ST_covers >> ( >> geomfromtext('POINT(10 18)',4326), >> geomfromtext('MULTIPOLYGON (((10 18,30 18,30 12,10 12,10 >> 18)))',4326) >> ) >> >> >> select postgis_full_version(); >> "POSTGIS="1.3.6" GEOS="3.1.0-CAPI-1.5.0" PROJ="Rel. 4.6.1, 21 August 2008" >> USE_STATS" >> I am using postgres 8.3.7 version and windows vista os. >> >> I read the release notes and the bug tracker and don't find any bug that >> fit the problem. >> >> In the meanwhile, i will download the postgres 8.3.8, 8.4.1 and try with >> newer versions of postgis 1.4.0 etc. >> >> Anyone has any clues? >> >> very thanks for yout help, >> Luigi Castro Cardeles >> >> >> 2009/9/21 Martin Davis <[email protected] <mailto: >> [email protected]>> >> >> >> 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]> >> <mailto:[email protected] >> <mailto:[email protected]>>> >> >> >> If it's on the boundary, is it within? >> Chris Hermansen [email protected] >> <mailto:[email protected]> >> <mailto:[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> >> <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]> >> <mailto:[email protected] >> <mailto:[email protected]>>> >> >> Date: Fri, 18 Sep 2009 10:01:32 >> To: PostGIS Users >> Discussion<[email protected] >> <mailto:[email protected]> >> <mailto:[email protected] >> <mailto:[email protected]>>> >> Subject: Re: [postgis-users] Problem with ST_WITHIN >> >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> <mailto:[email protected]> >> <mailto:[email protected] >> <mailto:[email protected]>> >> >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> <mailto:[email protected]> >> <mailto:[email protected] >> <mailto:[email protected]>> >> >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> <mailto:[email protected]> >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> >> -- Martin Davis >> Senior Technical Architect >> Refractions Research, Inc. >> (250) 383-3022 >> >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> <mailto:[email protected]> >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > > -- > Martin Davis > Senior Technical Architect > Refractions Research, Inc. > (250) 383-3022 > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users >
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