Removing polygons that look like lines in QGIS

Question

I calculated the difference between 2 massive polygon layers with the Difference tool in QGIS. I get the result I wanted…more or less. The problem is that there are a bunch of lines that appear in the middle of the polygons of interest. I tried getting rid of them by calculating their surface and getting rid of those that are really tiny (0.001, 0.01, 0.1ha, etc.), but I still haven't arrived to a satisfying result.

Does anyone have tips to get rid of these skinny line-looking polygons?

Answer 1

You may use the "Roundness" tool that :

Calculates the roundness of each feature and stores it as a new field. The input vector layer must contain polygons.

The roundness of a polygon is defined as 4π × polygon area / perimeter². The roundness value varies between 0 and 1. A perfect circle has a roundness of 1, while a completely flat polygon has a roundness of 0.

Then erase the polygons that fall below a certain roundness (you may need some trial and error to find the exact value that will remove all unwanted polygon without removing "good" polygon)