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

That's only true if you can also access the spatial boundaries of the zipcodes themselves.

In Australia, this turns out not to be true: the postal system considers their boundaries to be commercial confidential information and doesn't share them. The best we can do is the Australian Bureau of Statistics' approximations of them, which they dub "postal areas".