On Mon, 2009-02-16 at 11:35 +0000, John Stevenson wrote: > Hi, > > I have two questions, first a specific one, secondly a more general one. > > 1) I have some aerial photos that I want to mosaic. I am able to do > this with r.patch. However, the photos only cover about half of the > region. In the remainder of the region, I would like to show a shaded > relief map as a background to give context to the photos. When I > include the shaded relief map in the list to patch, it comes out as > varying shades of red. My question is therefore, what do I have to do > to the shaded relief map to turn it into an 'rgb image' that I can > include in r.patch.
Do you really want to patch the "shaed relief" map along with the orthophotos in one map? What about r.blend? If you insist on patching, then, I think, you would need to create 3 new versions of your shaded map which will correspond to R(ed), G(reen) and B(lue), rescale them to 0,255 (r.rescale). Then you patch them with the R, G and B mosaic's of the orthophotos and compose (r.composite) an RGB map. I would expect the shaded part to look grey-scaled since you will have the same pixel value in all of the R, G and B layers. But I am 100% sure that it will work. > 2) More generally, what is the best way of converting a good-looking > map into a georeferenced image e.g. by converting the elevation data > into rgb pixel colour data. Currently I would use d.out.file then > gdal_translate, but that is dependent on the screen resolution. What about "d.out.file in=YourMap out=YourMap resolution=2 # or resolution=4" ? > Cheers > > John Kind regards, Nikos _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
