I've got a block-level census dataset that I am attempting to aggregate using a 2-mile grid. Basically, I want each grid cell polygon to have a value equal to the sum of the total population of each census block inside it, plus the fraction of the population of each census block polygon intersecting it that is inside the grid cell (so that if a block is 50% in one cell and 50% in the other, each cell is assigned 50% of its population).

Is this something I should be thinking about in terms of a raster conversion? At a bit of a loss here, this type of geoprocessing is outside of my normal QGIS use.


1 Answer 1


Create a field in the block layer to store the original size of the polygons, then use the field calculator to calculate the size. Intersect the blocks with your grid. In the resulting layer create a field to store the size of the new polygons. Create a third field to store the weighted average population, divide the new polygon size field by the original size, and multiply that by the original population to get a weighted average population.

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