[GRASS-user] r.watershed MFD strange basin

Markus Metz markus.metz.giswork at googlemail.com
Wed May 9 03:30:42 EDT 2012


On Wed, May 9, 2012 at 9:19 AM, ivan marchesini
<ivan.marchesini at gmail.com> wrote:
> Dear Markus,
> thank you for your answer.
>
>> Please report if the stream segments are as expected, because the
>> determination of half-basins and basins is based on the stream
>> segments.
>
> this is the map of streams:
> http://imageshack.us/photo/my-images/232/streams.png/
>
> it seems fine..
>
>
>> If the stream segments seem out of place, something is wrong with the
>> identification of stream segments and you will need to look at flow
>> accumulation and check if that makes sense.
>
> this is the accumulation map:
> http://imageshack.us/photo/my-images/37/accumulation.png/
>
> the same as above...
>
>
>> If the stream segments seem to be ok, something is wrong with
>> determining the left and right side of a stream.
>
> this is the map of basins:
> http://imageshack.us/photo/my-images/11/basins.png/
>
> these are the half_basins:
> http://imageshack.us/photo/my-images/4/halfbasins.png/
>
>
> As you can see the problem arises for the half_basins and not only in
> one place. There are a lot of problems all around.

OK, now I have an idea where to look for the problem.
>
> I cannot explain which is the reason of this behaviour..
>
> if you like I can send you the DEM....

That would be very helpful!

BTW, what GRASS version are you using?

Markus M


More information about the grass-user mailing list