If you have a decently recent postgres, you could maybe save time (at least it is more readable):
*SELECT dmp.geom, dmp.valFROM * *my_raster a, ST_DumpAsPolygons(a.raster) AS dmp* CHeers, Rémi-C 2015-07-20 15:28 GMT+02:00 Elmehdi OUADOUD <ouadoud.elme...@gmail.com>: > For example: > > For a DEM raster X: 5261 Y: 4401 the vectorisation take 1 hour so I tintk > that something is wrong on my querie > > Le lundi 20 juillet 2015 15:18:42 UTC+2, Paul Ramsey a écrit : >> >> I would expect the vectorization of a raster to be fairly slow. >> Exactly how slow is another question. >> >> On Mon, Jul 20, 2015 at 6:14 AM, Elmehdi OUADOUD >> <ouadoud...@gmail.com> wrote: >> > Hi, >> > >> > I wonder know if the very very slow process is normal or i'm missing >> > something? >> > >> > thanks in advance >> > >> > Le mercredi 15 juillet 2015 10:11:46 UTC+2, Elmehdi OUADOUD a écrit : >> >> >> >> Hi All, >> >> >> >> I want to transfom a raster data to polygons but the process is too >> slow >> >> it takes 35 minutes. >> >> The querie i'm using : >> >> >> >> select (ST_DumpAsPolygons(a.raster)).geom, >> >> (ST_DumpAsPolygons(a.raster)).val >> >> from my_raster a >> >> >> >> Dimensions of my_raster >> >> >> >> X: 5261 Y: 4401 >> >> >> >> >> >> I'm missing something or it's normal ? >> >> >> >> >> > >> > _______________________________________________ >> > postgis-users mailing list >> > postgi...@lists.osgeo.org >> > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >> _______________________________________________ >> postgis-users mailing list >> postgi...@lists.osgeo.org >> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >> > > _______________________________________________ > postgis-users mailing list > postgis-users@lists.osgeo.org > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >
_______________________________________________ postgis-users mailing list postgis-users@lists.osgeo.org http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users