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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