I’m extremely grateful to Stacey Bricka of MacroSys and Shichen Feng of the Fresno COG to
provide insights and help in curing my logjam/frustrations.
I’ve uploaded a 10 example R-script to pull data from the CTPP 2017-2021 data for Parts 1,
2, and 3 at various geographic levels.
Here it is:
https://github.com/chuckpurvis/r_scripts/blob/main/ctpp1721_examples_1.R
r_scripts/ctpp1721_examples_1.R at main · chuckpurvis/r_scripts
github.com
I recommend having the CTPP Data Portal open in a web browser to help assist in selecting
tables and understanding geographic levels associated with any of the tables.
Most challenging was my attempt to pull tract-to-tract worker flow for my region. I think
there is an upper limit on the number of records that can be pulled in the API, somewhere
between 50,000 records and 5,000,000 records.
Next steps:
1. renaming variable names to be more mnemonic and memorable.
2. attaching GIS files using either tidycensus or the r package tigris.
3. mapping all of the cool patterns
4. summarizing tract-to-tract worker flows to county-to-county level, to ascertain data
loss due to lack of secondary allocation.
5. There probably should NOT be any data loss in any place-to-county or county-to-place
summary levels. Check this.
Hope this is of interest and use to the community.
cheers,
Chuck Purvis
Hayward, California
or contact me directly, at: clpurvis(a)att.net <mailto:clpurvis@att.net>
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