Rebecca wrote: > I have a map of local elevation that I would like to alter the > values of and re-class as a experiment to aid visualisation & > interpretation.
firstly, the r.reclass module might help, as may r.contour. > 1) Currently the cells are floating point with z-values like > 0.0151666768416021 - I would like to do is round the elevation > values to 2dp. there are a couple ways to do it, here's one: r.mapcalc "map.2dp = int(0.5 + (map.15g * 100))/100.0" the 0.5 is added because int() truncates instead of rounding. another common way is with log(mapname,10), but the above may be a little more obvious. > 2) I also like to reclassify the resulting map into 5cm wide > elevation ranges (reflecting the accuracy of the original data > capture) e.g. 0-4.90cm, 5-9.90cm etc erhm, I'm not exactly sure if that is a valid approach to look at the problem of instrument quantization (I'm fairly sure it isn't, both technically and fundamentally), but it is probably a job for r.reclass if you really want to do it; or adjust the multiply by--truncate--divide by r.mapcalc trick above to get it to round to whatever interval you like. Hamish _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user