zlacker

>>voxada+(OP)
ZIP codes are an emergent property of the mail delivery system. While the author might consider this a bad thing, this makes them "good enough" on multiple axes in practice. They tend to be:

- Well-known (everybody knows their zip code)

- Easily extracted (they're part of every address, no geocoding required)

- Uniform-enough (not perfect, but in most cases close)

- Granular-enough

- Contiguous-enough by travel time

Notably, the alternatives the author proposes all fail on one or more of these:

- Census units: almost nobody knows what census tract they live in, and it can be non-trivial to map from address to tract

- Spatial cells: uneven distribution of population, and arbitrary division of space (boundaries pass right through buildings), and definitely nobody knows what S2 or H3 cell they live in.

- Address: this option doesn't even make sense. Yes, you can geocode addresses, but you still need to aggregate by something.

>>jonas2+Xd
Contiguous enough by data travel time as well. A few people will get 5 ms more latency than the exact optimal route, but it’s not like your routes are exactly optimal anyway.

And don’t forget sales tax. Which is state + county + city