[GRASS-user] SRTM r.watershed at multiple scales

[Michel Wortmann]

Here is what I think is strange though about your explanation, Markus: 
If I first mask a watershed produced with r.water.outlet and then use 
r.watershed to produce subbasins, it doesnt include the entire area of 
the watershed but leaves small areas out, although these areas belong to 
it. Is this a threshold problem?

Tom, see image attached.

Michel

On 02/19/2014 04:42 PM, Thomas Adams wrote:
> I've been using GRASS 7 for this and have not seen a problem -- I hope 
> I'm not overlooking the issue. Michel, can you provide an image that 
> shows this?
>
> Thanks,
> Tom
>
> On Wednesday, February 19, 2014, Michel Wortmann 
> <wortmann at pik-potsdam.de <mailto:wortmann at pik-potsdam.de>> wrote:
>
>     Markus,
>     last year you asked me whether the r.watershed output is not
>     aligned to the r.water.outlet output in GRASS7 (s.b.). Ie. it
>     leaves small areas out. Back then, I wasnt using GRASS7, but I can
>     confirm now that it still does it and it is still rather annoying.
>     Have you ever heard of the reasons or attempted to fix this?
>     Thanks,
>     Michel
>
>     On 08/26/2013 03:25 PM, Markus Neteler wrote:
>
>         On 08/22/2013 08:52 AM, Markus Neteler wrote:
>
>             >>
>             >>Hi Michel,
>             >>
>             >>On Wed, Aug 21, 2013 at 1:18 PM, Michel Wortmann
>             >><wortmann at pik-potsdam.de>  wrote:
>             >>...
>
>                 >>>
>                 >>>As the r.watershed algorithm often leaves small
>                 areas at the edges
>                 >>>uncovered, you'll have to fill those before or
>                 after patching, otherwise
>                 >>>you'll have holes in your subbasin map.
>
>             >>
>             >>... just curious: does this happen still in the latest
>             GRASS 7 version?
>             >>
>             >>Markus
>
>
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>
> -- 
> Thomas E Adams, III
> 718 McBurney Drive
> Lebanon, OH 45036
>
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>
>



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