Dear Glynn Clements Is there a command r.grow.distance on GRASS? I tryed to find it on Native WinGrass, but it appears not be available, almost on 6.3 version.
Best wishes miltinho 2009/2/14 Glynn Clements <gl...@gclements.plus.com> > > Jan Hartmann wrote: > > > With that in mind, if the algorithm you propose would be indeed an > > approximation to weighted Voronoi polygons, *and* it wouldn't be all to > > hard to implement (I have no idea about that), would it make sense to > > propose this as a new RFC for GRASS? > > Oops; I spoke too soon. > > In retrospect, this won't work. r.grow.distance relies upon the fact > that once a cell falls out of consideration, it stays out. It will > only consider cells which either are from the current row, or were > used on the previous row. > > With distance scaling, this doesn't hold. A cell could be temporarily > overriden by much nearer cells with increased scale factors (lower > weights), then regain its influence once the distance increases. > > IOW, this isn't something which can implemented given the algorithm > used by r.grow.distance. Any algorithm which implemented distance > scaling would inevitably have worst-case memory usage proportional to > the number of non-null input cells, as you can never "forget" a cell > whose scale factor is lower than those currently being considered, as > it will eventually regain its influence. > > -- > Glynn Clements <gl...@gclements.plus.com> > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user >
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