On Thu, Feb 5, 2015 at 2:53 PM, Paulo van Breugel <[email protected]> wrote: > Check out the r.growth.shrink addon.
See also ticket #2368 [0] which includes a patch for r.grow.distance to shrink (distance from nearest NULL cell to be precise). Markus M https://trac.osgeo.org/grass/ticket/2368 > > On Thu, Feb 5, 2015 at 1:59 PM, Robert Nuske <[email protected]> wrote: >> >> Hi there, >> >> looking at some noisy raster map, I would like to clean up the patches >> (map >> consists only of one class and NULL) using basic mathematical morphology >> (dilation & erosion) in GRASS 7.0. >> >> >> The dilation can easily be achieved with r.grow. >> But the erosion seems not to be as straight forward. >> >> Since the example about shrinking was removed from the help page of r.grow >> in >> GRASS 7.0 (http://grass.osgeo.org/grass70/manuals/r.grow.html), I hoped >> for an >> easier way to carry out the erosion. Looking in vain for a raster command >> named shrink or erode, I tried a negative distance in r.buffer (-> error) >> and >> negative radius in r.grow (treated as absolute value). >> >> The following produce identical output with grown patches. >> r.grow in=mod_10_33 out=mod_10_33_1 radius=1.1 >> r.grow in=mod_10_33 out=mod_10_33_2 radius=-1.1 >> >> >> Any suggestions for a quick erosion? >> >> >> thanks >> Robert >> _______________________________________________ >> grass-user mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/grass-user > > > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
