Hey Robert!
Thanks for sharing! I've recently become fascinated by this topic. I've actually been playing with a different approach, one that uses hierarchical clustering on principal components of demographic information.
As an example, here's a start at a district map for NC using my method on county subdivisions.
It starts with computing principal components based on selected demographic data (i.e. percentage of males, percentage within census-defined age brackets, percentage within census-defined race groups, and percentage Hispanic for this example). I made sure to leave one group out with the percentages to avoid too strong of a correlation in the variables. I then selected the principal components accounting for at least 90% of the variation. From that, I created a weighted combination of the distance matrix for the PCs and a distance matrix from the county subdivision centroids (I used equal weighting here). Finally, I used hierarchical clustering with Ward's method to create 14 clusters, corresponding to the number of districts for NC.
The weighted combination approach was inspired by this R package:
https://cran.r-project.org/web/packages/ClustGeo/vignettes/intro_ClustGeo.html. I created this plot using JMP, but I've used R as well. While it's not necessarily as hands-free as your approach since someone would have to decide the number of principal components to use and the weighting scheme, I find it a nice balance in incorporating demographic information into the district creation, giving a nice display of the demographic distribution in the state, operating under the theory that districts should be representative of the state. Of course, it's not perfect, as you can see with the district "islands". Also, it currently does not attempt at keeping populations roughly equal among the clusters, something I'm still working on...
I'm curious as to your thoughts (and the thoughts of anyone else)! I'd especially be interested in any political ramifications of this approach, as I'm certain there are some.
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Caleb King, PhD
JMP
Raleigh, NC
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Caleb King
JMP
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Original Message:
Sent: 10-03-2021 14:34
From: Robert Agnew
Subject: CONGRESSIONAL DISTRICTING
Ideal US congressional districts untouched by human hands. https://github.com/raagnew/IdealCongressionalDistricting
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Robert Agnew
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