[GRASS-user] Problem with half basins becoming fragmented using r.watershed

[Massi Alvioli]

2018-07-16 18:53 GMT+02:00 Erin Hanan <ejhanan at gmail.com>:

Hi Erin,

let me forward your email to the list, since this may be interesting to others.

> Yes, this helps a lot; thank you! I've been reading through your paper and
> see that you mentioned one possible solution would be to remove slope units
> smaller than "cleansize", and then enlarge the adjacent slope units to fill
> the missing area using the r.grow. I'm curious whether I can also achieve
> this using r.area to remove the small half basins and then r.grow. I've also
> installed your software (r.slopeunits), and am planning to experiment with
> the different approaches today.
>
> By the way, I forgot to mention it in my original email, but yes, I tried
> several different threshold values. Interestingly, changing the threshold
> tended to change the size of larger half basins, but the sliver and
> fragmented basins always remained a problem.
>
> Anyway, thanks again for your very helpful email!

You are most welcome. Also, one of our cleaning approaches does
exactly what you suggest:
remove small areas and fill the empty spaces with r.grow.

Let us know if you get meaningful results!


Massi