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
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