Re: [postgis-users] ST_Clip
So the big square, in your image, is a whole 64x64 tile? I gave a try to the same kind of query here and everything is fine. Are you sure the circle is the same geometry used to clip? What about SELECT ST_PostGIS_Full_Version() Pierre -Original Message- From: postgis-users-boun...@postgis.refractions.net [mailto:postgis-users- boun...@postgis.refractions.net] On Behalf Of Paolo Cavallini Sent: Thursday, July 26, 2012 1:33 AM To: postgis-users@postgis.refractions.net Subject: Re: [postgis-users] ST_Clip Il 26/07/2012 01:54, Pierre Racine ha scritto: Is this table tiled? yes, -t 64x64 Why does your WHERE is about the rid and not ST_Intersects(rast, geom)? To make the clip on a tile only, and test how it works, I started following the example in http://www.postgis.org/docs/RT_ST_Clip.html , but got stuck early. Thanks. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Il 26/07/2012 16:33, Pierre Racine ha scritto: So the big square, in your image, is a whole 64x64 tile? not; I tried with a smaller buffer, I obtained a smaller square. I gave a try to the same kind of query here and everything is fine. Are you sure the circle is the same geometry used to clip? it should be: I relaunched the same command, just removing the ST_Clip What about SELECT ST_PostGIS_Full_Version() SELECT ST_PostGIS_Full_Version(); ERROR: function st_postgis_full_version() does not exist SELECT PostGIS_Full_Version(); POSTGIS=2.0.1 r9979 GEOS=3.3.3-CAPI-1.7.4 PROJ=Rel. 4.7.1, 23 September 2009 GDAL=GDAL 1.9.0, released 2011/12/29 LIBXML=2.8.0 RASTER Thanks a lot. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Paolo I am not sure if this is related to your issue but you may want to upgrade to GEOS 3.3.5 as there was an issue in 3.3.3 and 3.3.4 http://trac.osgeo.org/geos/ticket/558 Regards Stefano --- 41.95581N 12.52854E http://www.linkedin.com/in/stefanoiacovella http://twitter.com/#!/Iacovellas 2012/7/26 Paolo Cavallini cavall...@faunalia.it: Il 26/07/2012 16:33, Pierre Racine ha scritto: So the big square, in your image, is a whole 64x64 tile? not; I tried with a smaller buffer, I obtained a smaller square. I gave a try to the same kind of query here and everything is fine. Are you sure the circle is the same geometry used to clip? it should be: I relaunched the same command, just removing the ST_Clip What about SELECT ST_PostGIS_Full_Version() SELECT ST_PostGIS_Full_Version(); ERROR: function st_postgis_full_version() does not exist SELECT PostGIS_Full_Version(); POSTGIS=2.0.1 r9979 GEOS=3.3.3-CAPI-1.7.4 PROJ=Rel. 4.7.1, 23 September 2009 GDAL=GDAL 1.9.0, released 2011/12/29 LIBXML=2.8.0 RASTER Thanks a lot. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Il 26/07/2012 17:23, Stefano Iacovella ha scritto: Paolo I am not sure if this is related to your issue but you may want to upgrade to GEOS 3.3.5 as there was an issue in 3.3.3 and 3.3.4 http://trac.osgeo.org/geos/ticket/558 Thanks Stefano. I do not understand how this bug could affect my issue, however. Anyone confirms? I prefer to stick to geos 3.3.3, as this is the version in current Debian (soon to become stable), thus the one most used around, I guess. All the best. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
What happen if do a query like this: SELECT (gv).geom, (gv).val FROM (SELECT ST_PixelAsPolygons(ST_AsRaster(ST_Buffer(ST_Centroid(ST_Envelope(rast)), 0.5000), rast, ST_BandPixelType(rast, 1), 1, -1)) gv FROM hdr WHERE rid = 4 ) foo and display the resulting geometries labelled with the values? This is the first step of the clipping: creating a rasterized version of the buffer geometry aligned on the raster. Pierre -Original Message- From: postgis-users-boun...@postgis.refractions.net [mailto:postgis-users- boun...@postgis.refractions.net] On Behalf Of Paolo Cavallini Sent: Thursday, July 26, 2012 10:53 AM To: postgis-users@postgis.refractions.net Subject: Re: [postgis-users] ST_Clip Il 26/07/2012 16:33, Pierre Racine ha scritto: So the big square, in your image, is a whole 64x64 tile? not; I tried with a smaller buffer, I obtained a smaller square. I gave a try to the same kind of query here and everything is fine. Are you sure the circle is the same geometry used to clip? it should be: I relaunched the same command, just removing the ST_Clip What about SELECT ST_PostGIS_Full_Version() SELECT ST_PostGIS_Full_Version(); ERROR: function st_postgis_full_version() does not exist SELECT PostGIS_Full_Version(); POSTGIS=2.0.1 r9979 GEOS=3.3.3-CAPI-1.7.4 PROJ=Rel. 4.7.1, 23 September 2009 GDAL=GDAL 1.9.0, released 2011/12/29 LIBXML=2.8.0 RASTER Thanks a lot. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Il 26/07/2012 19:39, Pierre Racine ha scritto: What happen if do a query like this: SELECT (gv).geom, (gv).val FROM (SELECT ST_PixelAsPolygons(ST_AsRaster(ST_Buffer(ST_Centroid(ST_Envelope(rast)), 0.5000), rast, ST_BandPixelType(rast, 1), 1, -1)) gv FROM hdr WHERE rid = 4 ) foo and display the resulting geometries labelled with the values? This is the first step of the clipping: creating a rasterized version of the buffer geometry aligned on the raster. Here it is (qgis complains that it is not a valid layer, as it misses an id): geom | val +- 010320BB0B010005009D13253B5710384114AE47315EC652419D13253BBB10384114AE47315EC652419D13253BBB10384114AE473145C652419D13253B5710384114AE473145C652419D13253B5710384114AE47315EC65241 | 010320BB0B010005009D13253B5710384114AE473145C652419D13253BBB10384114AE473145C652419D13253BBB10384114AE47312CC652419D13253B5710384114AE47312CC652419D13253B5710384114AE473145C65241 | 010320BB0B010005009D13253BBB10384114AE47315EC652419D13253B1F11384114AE47315EC652419D13253B1F11384114AE473145C652419D13253BBB10384114AE473145C652419D13253BBB10384114AE47315EC65241 | 010320BB0B010005009D13253BBB10384114AE473145C652419D13253B1F11384114AE473145C652419D13253B1F11384114AE47312CC652419D13253BBB10384114AE47312CC652419D13253BBB10384114AE473145C65241 | (4 righe) -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Il 26/07/2012 19:54, Paolo Cavallini ha scritto: Il 26/07/2012 19:39, Pierre Racine ha scritto: What happen if do a query like this: SELECT (gv).geom, (gv).val FROM (SELECT ST_PixelAsPolygons(ST_AsRaster(ST_Buffer(ST_Centroid(ST_Envelope(rast)), 0.5000), rast, ST_BandPixelType(rast, 1), 1, -1)) gv FROM hdr WHERE rid = 4 ) foo and display the resulting geometries labelled with the values? This is the first step of the clipping: creating a rasterized version of the buffer geometry aligned on the raster. If I redo the query with the same buffer size as my previous one, I obtain a grid that encloses exactly the buffer; the raster is smaller. See attached. Thanks. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario attachment: Schermata del 2012-07-26 20:03:43.png___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Now what if you symbolize the value of the raster properly (1 = white and -1 = black) to display the shape of the buffer? -Original Message- From: postgis-users-boun...@postgis.refractions.net [mailto:postgis-users- boun...@postgis.refractions.net] On Behalf Of Paolo Cavallini Sent: Thursday, July 26, 2012 2:04 PM To: postgis-users@postgis.refractions.net Subject: Re: [postgis-users] ST_Clip Il 26/07/2012 19:54, Paolo Cavallini ha scritto: Il 26/07/2012 19:39, Pierre Racine ha scritto: What happen if do a query like this: SELECT (gv).geom, (gv).val FROM (SELECT ST_PixelAsPolygons(ST_AsRaster(ST_Buffer(ST_Centroid(ST_Envelope(rast)), 0.5000), rast, ST_BandPixelType(rast, 1), 1, -1)) gv FROM hdr WHERE rid = 4 ) foo and display the resulting geometries labelled with the values? This is the first step of the clipping: creating a rasterized version of the buffer geometry aligned on the raster. If I redo the query with the same buffer size as my previous one, I obtain a grid that encloses exactly the buffer; the raster is smaller. See attached. Thanks. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Is this table tiled? Why does your WHERE is about the rid and not ST_Intersects(rast, geom)? Pierre From: postgis-users-boun...@postgis.refractions.net [postgis-users-boun...@postgis.refractions.net] On Behalf Of Paolo Cavallini [cavall...@faunalia.it] Sent: Wednesday, July 25, 2012 6:42 PM To: PostGIS Users Discussion Subject: [postgis-users] ST_Clip Hi all. I may well be tired, but I cannot understand why: CREATE TABLE clip2 AS SELECT rid, ST_Clip(rast, 1,ST_Buffer(ST_Centroid(ST_Envelope (rast)),5000)) AS rast from hdr WHERE rid = 4; does not result in a circle, but in a square, contained in the buffer but smaller. See attached pictures, with the buffer in green, and the clipped raster inside. Any hint? Thanks. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] ST_Clip
Il 26/07/2012 01:54, Pierre Racine ha scritto: Is this table tiled? yes, -t 64x64 Why does your WHERE is about the rid and not ST_Intersects(rast, geom)? To make the clip on a tile only, and test how it works, I started following the example in http://www.postgis.org/docs/RT_ST_Clip.html , but got stuck early. Thanks. -- Paolo Cavallini - Faunalia www.faunalia.eu Full contact details at www.faunalia.eu/pc Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
