Ben:
Yes, I’m learning a lot about MCDs. I tried pulling Pennsylvania MCDs from TIDYCENSUS for the decennial census, but TIDYCENSUS (and the Census API) doesn’t have “MCD” as a standard geography. Instead, according to the Census Bureau documentation, MCDs in Pennsylvania are “county subdivision”.
I adapted a tidycensus script to pull “county subdivision” (aka Minor Civil Divisions, aka boroughs, townships and cities) for three sets of Pennsylvania PL 94-171 files: 2000, 2010, 2020. This script also has my best script used to calculate racial/ethnic diversity (using the dplyr “mutate” function.)
It appears that townships and boroughs can straddle counties. I wonder what happens with an MCD-to-MCD CTPP flow for PA?
Philadelphia is a huge county, with a 2020 population of 1,603,797. The best bet here is to use PUMA-of-Residence to PUMA-of-Work for just Philadelphia County. It’s a rectangular “trip table” with multiple rows (PUMAs) and just one column (Philadelphia County), but should be the finest grained commuter flow data for Philadelphia that has primary workplace allocation. (This is the case for the Bay Area, with 54 PUMAs of residence by 9 POWPUMAs — counties — of work!)
Here’s my script for Pennsylvania, 2000-2020, “The Best of PL 94171”, at MCD/County Subdivision level.
Chuck
Yes, Chuck, this is a data advantage for strong MCD regions--the workplace allocation is complete at this subcounty level that covers all areas of each county (as opposed to place, which doesn't have county-wide coverage). And our TAZs nest within our municipal boundaries, so fitting their flows to the MCD total is a good way to go for adjustments. The only issue in our region is that Philadelphia is both a county and MCD, so we don't get a subcounty control for our TAZ workplace fitting within our high pop/high employment urban center the way we do for our smallest boroughs and townships (we have one borough with a population of 10 and employment of 25).
Thanks for always pointing us to good resources and encouraging our experienced and burgeoning R users to explore CTPP data with that toolset!
Ben
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Ben Gruswitz, AICP | Manager, Socioeconomic & Land Use Analytics
(Pronouns: he/him)