Dimos wrote: > > > 44 CORINE CLC RGB color codes are mentioned for each of the 44 > > > land use classes at: http://dataservice.eea.europa.eu/download.asp?id=14234&filetype=.csv > > > > > > Can we classify a Landsat RGB image based on these rgb color codes > > > in GRASS GIS and how?
Markus: > > In my opinion it doesn't make much sense to use the RGB colors here > > since they are arbitrary (well, ok, ideally "close" to natural colors). I am trying to understand; there are 256^3 RGB possibilities (@ 8bits per channel) and CORINE have selected 44 of those possibilities to give labels to? Your chances of hitting those exactly are rather low. I suppose these are meant to be 3D spectral peaks somehow with the land-use category doing like a 3D form of a nearest-neighbor thiessen polygon. It seems a rather lossy and sensitive approach, ie it would be better to base it on all 7 bands & include some method to remove time of day/luminance issues. e.g. specify color normalization step first [eg i.landsat.rgb], or convert LANDSAT r,g,b pseudo-visual bands to HIS and classify on that (I'm guessing that hue would be less sensitive to sun angle). Nikos: > In my humble opinion, there is no way in this case to completely avoid > some manual digitisation of training samples, or edit the samples you > will extract from CORINE. .... > There is, on the web, a nice step-by-step which uses COREIN + i.smap on > Landsat [1]. .... > [1] http://www.custom-scenery.org/Building-Scener.331.0.html interesting. Hamish _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
