[gdal-dev] Convex hull with holes

[Markus Neteler]

On Fri, Mar 3, 2023 at 1:52 PM Paul Meems <bontepaarden at gmail.com> wrote:
>
> How can I algorithmically create a parcel border that accounts for islands or holes within the parcel based on a list of coordinates?
>
> While GDAL+GEOS has a Convex hull method, it only identifies the outer border.
>
> Has GDAL+GEOS a method that I can use to detect inner holes as well, such as in a donut-shaped field?
>
> The output can be json or shapefile, that doesn't matter.

GRASS GIS can do that: see the addon v.concave.hull (it is a Python script):

https://grass.osgeo.org/grass-stable/manuals/addons/v.concave.hull.html#creating-alpha-shapes

HTH,
Markus