Suppose a polygon layer in QGIS with differently shaped polygons (no multi-geometries, let's keep it simple). Is there a way to calculate some kind of roundness characteristic of the individual polygons. I imagine a value of 1 would be a perfect circle and 0.01 would be some kind of lengthily stretched out polygon (and the edge case, 0 would be a line). In the Field Calculator, it would probably look something like this:
exterior_ring( geom ) / $area
but I don't know what to put in
geom to get a useful number. Of course, if there is a more elegant solution to get some kind of measure of shape, I am open for suggestions.
I need this to get rid of really thin polygons after a clip operation. I put that in bold, because I just noticed that's a really useful information!
I'd need a solution I can use in Field Calculator or with some plugin.