NOTE: This began as a question on Stack Overflow, which has subsequently been closed. I also noticed a similar question about Most Up-To-Date Source for US Zip Code Boundaries, but I believe this question is different in that I'm not looking for boundaries as much as I'm looking for coordinates. Sorry for new newbie question. I'm not sure where to look to find reliable and up-to-date data.
We have a table in our database that has latitude and longitude geocode coordinates paired with US zip codes. A sample of the data looks like this:
Zip State Latitude Longitude
30000 GA 33.906553 -84.206311
30001 GA 33.810659 -84.607964
30002 GA 33.77429 -84.260712
30003 GA 33.906553 -84.206311
30004 GA 34.113832 -84.294578
30005 GA 34.079927 -84.221166
30006 GA 33.906553 -84.206311
30007 GA 33.968777 -84.43282
30008 GA 33.902022 -84.580318
30009 GA 33.906553 -84.206311
The problem is that our data hasn't been updated for a few years.
Where can I obtain (for free or for purchase) updated data for this table?
Answer
ZIP codes are a habitually abused geography. It's understandable that people want to use them because they are so visible and well-known but they aren't well suited to any use outside the USPS. ZIP codes aren't associated with polygons, they are associated with carrier routes and the USPS doesn't like to share those. Some ZIP codes are points e.g. a ZIP code may be associated with a post office, a university or a large corporate complex. They are used to deliver mail.
The Census Bureau creates ZIP Code Tabulation Areas (ZCTA) based on their address database. If it's appropriate to your work you could try taking the centroid of the ZCTAs. ZCTA Geography from the 2010 Census is available on the Census Bureau website.
See also: ZIP Code Geography and Mapping
No comments:
Post a Comment