4 ms·

Zip Codes Are Not Polygons (2001)

28 points by pizza 6y ago

pmiller2 6y ago
Oh, man, this gave me some serious flashbacks to when I used to work with ZIP code data on a regular basis. Besides the issues mentioned here, the following are also true: * ZIP codes can map to a single building: https://convene.com/catalyst/buildings-new-york-city-own-zip-code/ https://convene.com/catalyst/buildings-new-york-city-own-zip... * Conversely, the largest ZIP code in the country (89049, coincidentally, also in Nevada) encompasses an area of about 10,000 square miles: https://www.npr.org/sections/thetwo-way/2013/07/01/197623129/the-zip-code-turns-50-today-here-are-9-that-stand-out https://www.npr.org/sections/thetwo-way/2013/07/01/197623129... * ZIP codes can map to more than one state or county: https://gis.stackexchange.com/questions/53918/determining-which-us-zipcodes-map-to-more-than-one-state-or-more-than-one-city https://gis.stackexchange.com/questions/53918/determining-wh... * ZIP codes can, and do change: https://fas.org/sgp/crs/misc/RL33488.pdf https://fas.org/sgp/crs/misc/RL33488.pdf As a result, ZIP codes are not the most useful method to use when referring to a geographic area, unless, that is, you happen to be a USPS carrier attempting to deliver a letter or package. Unfortunately, like Social Security numbers, ZIP codes have been shoehorned into all sorts of places where they don't really work (e.g. statistical surveys, to give an idea where someone lives). It's a mess. My advice is that if you're looking to use ZIP codes for pretty much anything besides mailing stuff, don't do it, unless you know what you're doing. Even if you know what you're doing, think really, really hard before using a ZIP code for something it's not actually intended for.
- watersb 6y ago
  If we count ZIP+4 codes, my garage has its own ZIP code. It's a single car garage (but platted on a distinct tract from the house). In a village in the desert southwest, I guess they had extras numbers.
- ThePadawan 6y ago
  Could not agree more. I have personally also made the experience that (Swiss) zip codes don't refer to geography at all: e. g. there are zip codes reserved for universities (that are used regardless of campus).
wodenokoto 6y ago
Great little article. Straight to the point, easy to understand and with a good message. Kinda a shame that it is hidden away in an archive.
JJMcJ 6y ago
Sales tax, ZIP code crosses county line, one county has a sales tax surcharge, the other doesn't. Not ZIP precisely, but even the "City" causes problems. The address is the name of the post office that delivers your mail, not the municipality where the address is located.

28 points by pizza 6y ago

Oh, man, this gave me some serious flashbacks to when I used to work with ZIP code data on a regular basis. Besides the issues mentioned here, the following are also true: * ZIP codes can map to a single building: https://convene.com/catalyst/buildings-new-york-city-own-zip-code/ https://convene.com/catalyst/buildings-new-york-city-own-zip... * Conversely, the largest ZIP code in the country (89049, coincidentally, also in Nevada) encompasses an area of about 10,000 square miles: https://www.npr.org/sections/thetwo-way/2013/07/01/197623129/the-zip-code-turns-50-today-here-are-9-that-stand-out https://www.npr.org/sections/thetwo-way/2013/07/01/197623129... * ZIP codes can map to more than one state or county: https://gis.stackexchange.com/questions/53918/determining-which-us-zipcodes-map-to-more-than-one-state-or-more-than-one-city https://gis.stackexchange.com/questions/53918/determining-wh... * ZIP codes can, and do change: https://fas.org/sgp/crs/misc/RL33488.pdf https://fas.org/sgp/crs/misc/RL33488.pdf As a result, ZIP codes are not the most useful method to use when referring to a geographic area, unless, that is, you happen to be a USPS carrier attempting to deliver a letter or package. Unfortunately, like Social Security numbers, ZIP codes have been shoehorned into all sorts of places where they don't really work (e.g. statistical surveys, to give an idea where someone lives). It's a mess. My advice is that if you're looking to use ZIP codes for pretty much anything besides mailing stuff, don't do it, unless you know what you're doing. Even if you know what you're doing, think really, really hard before using a ZIP code for something it's not actually intended for.

watersb 6y ago
If we count ZIP+4 codes, my garage has its own ZIP code. It's a single car garage (but platted on a distinct tract from the house). In a village in the desert southwest, I guess they had extras numbers.
ThePadawan 6y ago
Could not agree more. I have personally also made the experience that (Swiss) zip codes don't refer to geography at all: e. g. there are zip codes reserved for universities (that are used regardless of campus).

wodenokoto 6y ago

Great little article. Straight to the point, easy to understand and with a good message. Kinda a shame that it is hidden away in an archive.

JJMcJ 6y ago

Sales tax, ZIP code crosses county line, one county has a sales tax surcharge, the other doesn't. Not ZIP precisely, but even the "City" causes problems. The address is the name of the post office that delivers your mail, not the municipality where the address is located.