blakek
commented
2 years ago You're right. The README.md should be updated to call this out better.
The reason they're missing is this is using ZIP Code Tabulation Areas by the US Census Bureau.
From the Census site:
Some ZIP Codes represent very few addresses (sometimes only one) and therefore will not appear in the ZCTA universe.
There's other reasons a ZIP code wouldn't be listed here, but that's by far the most common reason I've noticed.
Looking at the population for 99950, I suspect it's missing for the reason above. It's likely the nearby 99918 was used for census purposes. For example if you look in Google Maps, 99918 shows as expected, but 99950 shows a staffing office location.
However, if you know of a better list of ZIP codes, I'd be interested in using it! Ones I looked for before using the ZCTA list had at least one of these issues:
- not open-source
- expensive
- outdated or mixes outdated information with updated (populated, changed ZIP show in wrong location)
I spot checked zip codes and noticed there are a few missing zip codes, such as: 99950