Rich, On Sat, Apr 7, 2012 at 3:51 PM, Rich Shepard <[email protected]>wrote:
> On Sat, 7 Apr 2012, Margherita Di Leo wrote: > > r.basin produces several maps for every run, which are flow direction, >> accumulation, Horton ordered streams etc.. Prefix parameter is simply a >> string given by the user in order to distinguish all the maps produced by >> a >> single run of the program, i.e. every set of coords for outlet. For >> example, >> > > madi, > > I thought this is the case, but wanted to know rather than assume. > > > Threshold parameter is the same of r.watershed. 'Autothreshold ' flag' >> simply uses a threshold area of 1 km^2 and is intended as a tentative. >> > > Again, rather than assuming I wanted to be sure I understood. > > > For what concerns r.stream.basin, it is a typo in the documentation, >> correct is r.stream.basins, thanks for pointing me out, I just updated it >> in the description file. >> r.wf.py and r.ipso.py are in the addOns repository: >> > > Ah, I see why they did not download for me: I added the .py extention to > the g.estension command. Now I know to leave it off. > > > Please note that r.basin is intended to work with only one outlet at time. >> This means you should script it in a for cycle if you run it for several >> outlets. >> > > I understand this. > > > You can't give to r.basin the coordinates directly from a vector map. >> > > But, can I use the coordinates of a rasterized stream network? No. Do you think this would be an useful add? If so, I could work on it when I have some spare time.. Let me know. > > > I have indicated to run r.stream.extract before r.basin because most of >> the >> times the calculated stream network doesn't match with the natural one, so >> that your coordinates should be adjusted to match the calculated stream >> network in order to get a result from r.basin. By the way, in a first run >> you can give a try with your coordinates. >> > > The outputs of r.stream.extract on two different project sub-watersheds > are, as far as I can see on the display, only about 5-10% of the vector > stream network, and all at the lower ends of the basins in which they > appear. I can send screen shots if you'd like to see the differences. > AFAICT this could be due to an odd value for the threshold, or a g.region or mask related problem. Please try setting g.region to match the elevation map, removing the mask and setting a lower threshold value. > > After downloading and building the 'missing' three modules I'll try > v.to.rast on the natural stream network (at 1:24,000 scale, just like the > elevation data) and see what r.basin tells me. > Let me know about your results. madi > > Many thanks, > > > Rich > > ______________________________**_________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/**mailman/listinfo/grass-user<http://lists.osgeo.org/mailman/listinfo/grass-user> > -- Ing. Margherita Di Leo, Ph.D.
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