Or ST_Reclass() reclassifying everything > 10 to nodata... > -----Original Message----- > From: postgis-users-boun...@lists.osgeo.org [mailto:postgis-users- > boun...@lists.osgeo.org] On Behalf Of Rémi Cura > Sent: Wednesday, May 27, 2015 9:31 AM > To: PostGIS Users Discussion > Subject: Re: [postgis-users] Using Postgis raster for water elevation > > Hey, > > > Map Algebra? > > (custom function with a thresholding?) > > > > Cheers, > > Rémi-C > > > 2015-05-27 14:57 GMT+02:00 Gabriel Vatin <gabriel.va...@kinaxia.fr>: > > > Hello all, > > I'd like to have some feedbacks on an operation that should be > possible with Postgis raster, but I can't find out how to do this. > I have a whole raster of French DEM (elevation data) stored on > PostGis, with tiled objects. That makes a table with some 14.000 rows of > data: france_mnt (rid, rast, filename) > With ST_Value(france_mnt.rast, geometry), I can retrieve the > elevation of a given coordinates in the geometry object. > > I'd like to create a new raster, on the fly, with a maximum value of > elevation, such as : all pixels with value < 10 > This could be used for mapping water elevation in a area, for > instance. > > Anyone has already done this? I'll be happy to have some tips on > the function to use. > Thanks! > > Gabriel > > _______________________________________________ > postgis-users mailing list > postgis-users@lists.osgeo.org > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > >
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