[GRASS-user] Classify basins as "narrow"

[Markus Neteler]

On Wed, Sep 2, 2020 at 1:27 PM Ken Mankoff <mankoff at gmail.com> wrote:
>
> Hi GRASS list,
>
> I'd like to detect "narrow" features in GRASS. The attached screenshot shows some basins (thick) and streams (thin) and some regions (hatched). These regions are spurious because the basin is narrow here. I'd like to estimate narrowness with an algorithm.
>
> I've looked into r.grow.distance r.distance and v.distance but haven't been able to imagine a solution yet. Can anyone on this list suggest something?

Perhaps the compact measure of

https://grass.osgeo.org/grass78/manuals/v.to.db.html
--> compact: compactness of an area, calculated as compactness =
perimeter / (2 * sqrt(PI * area))

could help here?

Best
Markus