On Nov 19, 2021, at 7:39 PM, Charles Purvis <clpurvis@att.net> wrote:
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We’re in the middle of a 90 day period to delineate new, Census 2020-based PUMAs (Public Use Microdata Areas) (November 2021 - January 2022).
PUMAs are used not only in Census Bureau PUMS (Public Use Microdata Sample data); but in standard tabulations (1-year, 5-year) of American Community Survey (ACS) data.
This PUMA development process is basically of interest to MPOs, State DOTs, academics and researchers of area with counties greater than 200,000 population (potentially splittable counties).
Read more about the PUMA process here:
The Census Bureau process focuses on the use of the free GIS system QGIS and the free add-on GUPS (Geographic Update Partnership Software) to prepare new PUMAs. Read through this carefully, but understand that the MPO staff don’t necessarily need to use QGIS + GUPS to prepare the tract-to-PUMA equivalency files. This CAN be done in other software (ArcGIS?) and then transmitted to your State Data Center so they can do the necessary edit checks and transmittal of final statewide proposals to the Census Bureau. Recommendation: work with your State Data Center on how to transmit the necessary tract-to-PUMA equivalency files.
For the San Francisco Bay Area, I used both R and QGIS for this process. Both R (using R Studio software) and QGIS are free — in my price range!
Attached is my R script which was used to obtain tract-level data using the TIDYCENSUS package; place-level data using TIDYCENSUS; and old Census 2010-based PUMAs using the TIGRIS package. I had to use the SF package (simple feature) to do some basic GIS processes in R, before I exported relevant SHP files that I could use in QGIS. Use ArcGIS or other GIS packages, of course.
I was able to expand the number of PUMAs in the nine-county San Francisco Bay Area (population=7.765 million) from 55 PUMAs (2010 Census) to 63 PUMAs (2020 Census). And we should have plenty of time to debate and deliberate in our local community (counties, cities, transit operators, academics, PUMA/PUMS users) before handing proposals over to the State Data Census & the Census Bureau.
Hope this helps!
Chuck PurvisHayward, California
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