I would like to add in the attributes of each of my roof boundaries (red polygons, which sometimes overlap) the sum of the surfaces of the (green) surfaces.
I have already tried "join attributes by locations" but some of the green surfaces are sometimes just partially on the red limits.
It leads to an error:
the area added in the attributes is the whole area of the green surface and NOT only the partial overlap
What would be the easiest approach for working with Qgis, taking into account that there are a lot of data?