On Wed, 2008-10-15 at 12:01 +0000, christian Brandt wrote: > Dear list, > > I imported a georeferenced orthophoto (tif with tfw) with all bands (RGB) > using r.in.gdal. > > The result (3 raster layers red, green and blue) looks like very , what means > that there is not much to recognize any more on the orthophoto. > > Any suggestions how to enhance the of the orthophoto? > > Regards > > Christian
Hi Christian! Splitting the colour orthophoto in three channes means that you are now able to manipulate the 3 levels of this multi-dimensional "stack" of information the way you want. You can for example use all 3 channels to perform a classification or you can selectively use only 2 or 1! It always depends upon what you want to do. You can of course view the "normal" RGB image (with d.rgb where r=red channel, g=green channel, b=clue channel). Now if viewing/visual interpretation is your aim, you can create a composite (r.composite) and use this as a single image for viewing (not for classifying). About the colors you can either stretch all channels before creating the composite or you might want to look in i.landsat.rgb (it's a very nice auto-color-balancing tool). FWIW, I think that GRASS is not well doing when it comes to pan/zoom an image or visually cross-compare it with another. I prefer to open the images with OpenEV (opening the raster maps from the /cellhd directory or exporting them as tiffs). Hope this helps, Nikos _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
