I'm using QGIS 1.8 on OSX 10.8.3.
I have a polygon shapefile of all of the US state legislative districts.
I also have a layer of points that are centroids of US Census Tracts, with a field for the population of the tract.
How do I generate a layer of points that are the weighted mean of each census tract point within each legislative district?
My hunch is to play with spatial joins and use fTools to do mean coordinates, but I'm not sure how to calculate the mean for each polygon instead of the whole layer itself.