Hi, I have a 16244x12706 GeoTIFF file (600dpi scan) which is made up of 7 colors but came as a 3-band 24bit True Color image.
I can import with r.in.gdal as red,green,blue bands, but it's huge and slow. I can't use pnmquant as it overflows the RAM. (I have 2GB physical + 2GB swap) I tried Indexing it to a small number of colors with the Gimp, but after the process the colors were all changed. I can index as 256 colors with little color change in the Gimp, but that is still 249 more than I need. I want a CELL map with cat=[1,2,3,4,5,6,7] values with RGB set for each category by r.colors. I guess I can use the Gimp to index to 7 (wrong) colors, import that into GRASS, then use r.colors + the Gimp's eye-dropper tool on the original to fix them. Staying with the original 3-band import, how to find the 7 peaks in the r.composite histogram, filter out anything that isn't a peak by changing its value to be that of the nearest peak, and reclass to 1-7? As r.reclass can take ranges for input, I guess I can be a bit sloppy in finding the peaks and use the result of r.stats as input to r.reclass, then extract a "hardcopy" from the reclass map with r.mapcalc a=b. ? any one have a bright idea how to do this with minimal data loss ? thanks, Hamish _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
