[GRASS-user] stream network

[Stefan Lüdtke]

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 <will.openfields at gmail.com
> <mailto:will.openfields at gmail.com>> 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 <jsc.eco at gmail.com
>     <mailto:jsc.eco at gmail.com>> 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
> 
> 
> 
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> 
> 
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-- 
Stefan Lüdtke

Section 5.4-  Hydrology
Tel.: +49 331 288 2821
Fax: +49 331 288 1570
Email: sluedtke at gfz-potsdam.de

Helmholtz-Zentrum Potsdam
Deutsches GeoForschungsZentrum GFZ
(GFZ German Research Centre for Geoscience)
Stiftung des öff. Rechts Land Brandenburg
Telegrafenberg, 14473 Potsdam
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