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
This is a tangent, but addresses are also way more complicated than most people realize - especially if you’re relying on a user to input a correct address or if you need to support multiple countries, somewhere with unique addresses like Queens[0], or you need to differentiate between units of a specific street address that uses something other than unit numbers for a unit designation.

At that point you need something like Smarty[1] to validate and parse addresses.

[0]: https://stackoverflow.com/questions/2783155/how-to-distingui...

[1]: https://www.smarty.com/

>>ericra+Um
Yes, unfortunately, their assertion that everyone knows their zip code is wrong. People often write a neighboring code, and the post office just delivers it.

Similar issues for city name, of course.

>>nitwit+xs
This sounds like the person doesn't know the receiver's zip code. Why are you extending that to not knowing their own zip code? Are they mailing something to themselves?

>>steeze+aG
People often give out their mailing address, and may be misinformed about their zip code.

If you get close enough, it usually gets handled in the local sort, but not always.

On cities, the mailing address city really is the name of the post office that handles your delivery route. Often there's a relationship with the city you live in, but there's cases both ways --- I used to live outside city limits, we had a census designated place name, a municipal sanitary district and had a fire department at one time... but never a post office, so our mailing address used the nearby city name, where our post office resided. The place name had an incorporated city on the other side of the state, so using that wouldn't be great.

Nowadays, post offices often have a list of alternative place names, so where I live now, I can pick between the incorporated city name, the nearby large city where a post office that processes all my mail is located, or any of the numerous small post offices that once served my city.