I'm quite new to QGIS.
I have one layer that is a quadratic grid with a different population in each square, and I have another layer with two polygons that I got from the Travel Time plugin. I want to calculate how large a population each travel time polygon covers. I have done it when there is no overlapping between two polygons by using Spatial Join in MMQGIS.
However, I don’t know how to do this when there is overlap between the polygons. When there is overlap, I want to split the population evenly between the polygons. I also want to be able to do this when there are more than two overlapping polygons.
Do you know how to do this?