I am new to QGIS.
I have a dataset with Baltimore neighborhoods, and then a series of datasets for Baltimore census tracts dating back to the 1930s. My goal is to look at how population and the amount of units has varied over the years for each neighborhood. However, neighborhoods and census tracts overlap in imprecise ways so that the following situations occur:
- Most neighborhoods contain multiple census tracts.
- Some census tracts overlap multiple neighborhoods.
- Some census tracts contain more than one complete neighborhood.
I think the best way to handle this will be to aggregate population counts by the weighted ratio of a given census tract area's containment in a given neighborhood. As some examples (see image as well) In the 1940 census, Reservoir Hill (neighborhood) contains 100% of CT 0132 (pop 5,070), 80% of CT 0131 (pop 4,795), 20% of CT 0133 (pop 6263), and a tiny sliver (let's say 2%) of CT 0134 (pop 3,934). So 5070 + (4795*.8) + (6263*.2) + (3934*.02)=10,237.
Parkview/Woodbrook is an entire neighborhood contained within the CT 0134 in 1940. Since maybe 10% of 0134 is contained in the neighborhood, pop 3,934*.1=393.
I know this will introduce some aggregation bias, but I think it's likely a lot more accurate than just finding the center point of each census tract and then assigning the total population to whatever neighborhood contains the center point.
Is there a reasonably feasible way to conduct this type of analysis and calculations w/in QGIS?
Here's sort of what I'd envision as an output of quasi-arrays in the "Neighborhood" shapefile:
This is the most related issue I've found so far, though I've never used PostGIS.