Or, if you want to filter by area (POLYGON and MULTIPOLYGON), see this: http://www.spatialdbadvisor.com/postgis_tips_tricks/92/filtering-rings-in-polygon-postgis regards Simon On Fri, 06 Feb 2009 05:29:15 +1100, Kevin Neufeld <[email protected]> wrote:
> Use ST_DumpRings to extract the rings, then exclude the ones you don't want > and then rebuild your polygon. > http://postgis.refractions.net/documentation/manual-svn/ST_DumpRings.html > > ie. > -- A polygon with 6 inner rings, we exclude all but rings 3 and 5 > SELECT ST_AsText(ST_BuildArea(ST_Collect(geom))) AS the_geom > FROM (SELECT (ST_DumpRings( > 'POLYGON (( 0 0, 0 7, 10 7, 10 0, 0 0 ), > ( 1 4, 3 4, 3 6, 1 6, 1 4 ), > ( 4 4, 6 4, 6 6, 4 6, 4 4 ), > ( 7 4, 9 4, 9 6, 7 6, 7 4 ), > ( 1 1, 3 1, 3 3, 1 3, 1 1 ), > ( 4 1, 6 1, 6 3, 4 3, 4 1 ), > ( 7 1, 9 1, 9 3, 7 3, 7 1 ) > )'::geometry)).*) AS foo > WHERE NOT ( ARRAY[1,2,4,6] @> path ); > > the_geom > ------------------------------------------------------------------------------ > POLYGON((0 0,0 7,10 7,10 0,0 0),(7 4,9 4,9 6,7 6,7 4),(4 1,6 1,6 3,4 3,4 1)) > (1 row) > > Cheers, > Kevin > > Albert Krueger wrote: >> Hi at all, >> >> I have a Donut-Polygon with a number of Innerrings. Now I would like to >> delete some Innerrings. For Example I have a polygon with five >> Innerrings. ButI want to delete the second and the fourth Innerring. Has >> anyone an idea how I can get a polygon with only three Innerrings >> (1,3,5) then? >> >> Thank you! >> >> Best regards >> >> Albert >> >> >> _________________________________ >> l...@lycos ist jetzt ganz neu - melde dich kostenlos an, lerne neue >> Leute kennen und finde deinen Flirt! >> Jetzt flirten! >> <http://bc.lycos-europe.net/lnl/bc.php?loveatlycos_promo_mailsig|http://love.lycos.de/start.action?utm_campaign=mp&utm_source=mailsig> >> >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > -- SpatialDB Advice and Design, Solutions Architecture and Programming, Oracle Database 10g Administrator Certified Associate; Oracle Database 10g SQL Certified Professional Oracle Spatial, SQL Server, PostGIS, MySQL, ArcSDE, Manifold GIS, FME, Radius Topology and Studio Specialist. 39 Cliff View Drive, Allens Rivulet, 7150, Tasmania, Australia. Website: www.spatialdbadvisor.com Email: [email protected] Voice: +613 9016 3910 Mobile: +61 418 396391 Skype: sggreener Longitude: 147.20515 (147° 12' 18" E) Latitude: -43.01530 (43° 00' 55" S) NAC:W80CK 7SWP3 _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
