[GRASS-user] stream network

[Markus Metz]

On Wed, Mar 2, 2016 at 8:42 PM, Janet Choate <jsc.eco at gmail.com> 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.

Please note that r.watershed does not require filled depressions. If
you want a properly connected stream network in vector format, use
r.stream.extract.

> thanks,
> Janet
>
> On Wed, Mar 2, 2016 at 11:22 AM, Will Fields <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> 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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