Readme for geographic crosswalks
Brendan Price
July 29, 2014

This folder contains crosswalks mapping geographic areas to commuting zones.

(1) The file "cw_cty_czone_mod.dta" maps counties into commuting zones. It is a modified version of the file "cw_cty_czone.dta", available at David Dorn's website (http://www.cemfi.es/~dorn/data/cw_cty_czone.zip), with the following changes:
- I add an observation mapping FIPS code 12086 into CZ 7000. This accounts for Miami-Date County, Florida, whose FIPS code changed from 12025 to 12086.
- I add an observation mapping FIPS code 8014 into CZ 28900. This accounts for the creation of Broomfield County, Colorado.
Note that these county changes are described in http://www.cemfi.es/~dorn/data/FIPS_County_Code_Changes.pdf.

(2) The file "cw_czone_state.dta" maps commuting zones into states (note that these states do not correspond exactly to true US states, since commuting zones sometimes straddle state borders). It is downloaded without modification from http://www.cemfi.es/~dorn/data/cw_czone_state.zip.

(3) The files "cw_czone_region.dta" and "cw_state_region.dta" map commuting zones and states into Census divisions. Note that the variable "region" actually denotes the 9 Census *divisions* (rather than the 4 Census *regions*).