I have 2 polygon layers which can be found here.
The two layers are overlapping. The first contains a map of the German counties in 1928 and the second the counties how they are in 2014.
The 2014 layer contains information about the population (called Bev in the dataset). Is it possible to project the population attribute from the one polygon layer to the other?
To be a bit more specific:
Consider the situation where I have 2 counties in the layer with the population attribute but in the same area on the other layer there is only 1 county. Can QGIS aggregate the population of the two counties and write this information into the other layer?
If this works, is there also a way to do it when the layer with the information has in a specific area only 1 county but there are 2 counties in the other layer? In this case I would like to split the population proportional to the size of the county.
Best Answer
If you really want to get number values based on ratio of polygon area overlap between layers (L1 = counties_2014, L2 = german empire 1928):
If you done all well you should get about 77 million people distributed based on L2 counties area out of 81 million in L1.