On Sat, Jan 24, 2009 at 3:52 AM, Kenneth Brookes <ken_broo...@hotmail.com> wrote: > > Hi Timmie > > I am not very familiar with GRASS GIS either but I'm trying to learn. > However, GRASS does have the tools to perform multi-spectral image > classification.
Besides that you can also generate indices or do a transform. See for example http://grass.osgeo.org/grass64/manuals/html64_user/i.tasscap.html -> 'Wetness' Tasseled Cap component 3 (screenshot) which identified the lakes near Raleigh, North Carolina. Thresholding that image will extract the lakes. Using additional water-sensitive indices and image classification (perhaps also r.texture to generate synthetic channels) will help to create a set of potential water body maps. Finally, adding them with r.mapcalc gives a kind of probability map for water bodies. The result can then be thresholded (r.mapcalc) to generate a Yes/No (1/null) map ready for vectorization with r.to.vect. Just some ideas, Markus _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user