I've got a DEM raster that I've analysed for slopes. I now need to generalise it, and it sounds like using gdal_sieve is the best way.
However, whenever I try to run it, the resulting raster is always entirely black. It seems to set each pixel to the NoValue value (in my case, -9999). My data is in floats, and goes from 0 to about 34.3 or something like that (apart from NoValues obviously).
I have used Raster>Conversion>Translate to get it to an integer, and also the Raster>Calculator to multiply the values by 100, but the results are still 0.