Stefan, unfortunately - it's not something that is apparent by appearance. the problem was discovered after using the raster map as an input to another program - then it became clear that there were places where there were no upstream or downstream neighbors to some segments. thanks, Janet
On Thu, Mar 3, 2016 at 1:38 AM, Stefan Lüdtke <[email protected]> wrote: > Hi Janet, > > can you provide a screenshot of the river network, I think that helps to > understand what is going on in your specific case?! > > Cheers, > Stefan > > On 02/03/16 20:42, Janet Choate wrote: > > Hi Will, > > When running r.watershed on a small 35 hectare watershed, it produces a > > fully connected stream network. However, when running r.watershed on a > > 6400 hectare watershed, the stream network is not fully connected. > > No preprocessing with regards to merging different raster maps, however, > > I did try using r.fill.dir first to deal with any possible depressions > > that might be causing non-connected stream segments. > > thanks, > > Janet > > > > On Wed, Mar 2, 2016 at 11:22 AM, Will Fields <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hi Janet, > > > > Can you give some more information about what you mean by larger > > watershed basins? Did you do any preprocessing of the elevation > > raster before you tried to extract the stream networks? Were you > > using an elevation raster that had been merged from different > > rasters? I've ran into issues in the past where "seams" along the > > original edges of a raster resulted in odd stream networks. > > > > Will > > > > On Wed, Mar 2, 2016 at 11:40 AM, Janet Choate <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hi GRASS community, > > When creating a stream network with r.watershed, I end up with > > some isolated stream segments - particularly in larger watershed > > basins. Does anyone know how to generate a stream network that > > is fully connected, or how to correct this issue? > > thank you, > > Janet > > > > > > > > _______________________________________________ > > grass-user mailing list > > [email protected] <mailto:[email protected]> > > http://lists.osgeo.org/mailman/listinfo/grass-user > > > > > > > > > > > > -- > > Tague Team Lab Manager > > 1005 Bren Hall > > UCSB, Santa Barbara, CA. > > > > > > _______________________________________________ > > grass-user mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/grass-user > > > > -- > Stefan Lüdtke > > Section 5.4- Hydrology > Tel.: +49 331 288 2821 > Fax: +49 331 288 1570 > Email: [email protected] > > Helmholtz-Zentrum Potsdam > Deutsches GeoForschungsZentrum GFZ > (GFZ German Research Centre for Geoscience) > Stiftung des öff. Rechts Land Brandenburg > Telegrafenberg, 14473 Potsdam > ------------------- > > PGP Public Key: http://bit.ly/13d9Sca > > -- Tague Team Lab Manager 1005 Bren Hall UCSB, Santa Barbara, CA.
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