maps.huge.info

I just posted a new reverse geocoder for the US based on the Tiger/Line 2005SE database. It's not as accurate as my USPS based system but it does cover areas that mail isn't delivered like rural routes, interstates and other roads. The zip codes returned are not validated, so I don't recommend using these for anything but informational purposes at this time. There are 90,000,000 records in the database.

http://www.usnaviguide.com/revtigerrest.pl

Parameters: (case sensitive)

lat
long

Example:

http://www.usnaviguide.com/revtigerrest.pl?lat=35&long=-90

The return is an xml file. This is a simple REST interface.

The usual 150 hit limit per every two hours holds on this site as well. If you need more, let me know.

A new version of the zip code boundary map has been released today! This one displays actual USPS zip code areas instead of ones based on the Tiger/Line ZCTA's. The results are the most accurate free USPS zip code boundary maps available anywhere on the internet. These new maps are up to date as of November/2006 and will be updated quarterly.

USPS Zip Code Boundary Maps

The usual 150 hits per every 120 minute limit applies to this map.

-John Coryat, USNaviguide.com

Officially, there is no such thing as a zip code boundary, a zip code area or any geographic representation of a zip code. To the USPS, a zip code is a delivery route, not an area. Here's a good explanation from the Census bureau comparing the ZCTA to the USPS Zip Code.

http://www.census.gov/geo/www/tiger/tigermap.html#ZIP

The difference between the 2000 census ZCTA and the 2005SE based ZCTA's is the age of the data. The 2005SE ZCTA's are dated as of December (or there abouts) 2003 and the 2000 census ZCTA's are sometime before 2000, probably 1998.

My USPS Zip Code area maps are a combination of the Tiger mathematical representation of the US and my AIS USPS Zip+4 based Reverse Geocoder to produce up to date zip code areas. As there are no "official" zip code areas, each company that produces a map showing such a thing has calculated a close approximation of what a zip code area could look like. In my case, I believe my maps are pretty accurate.

To produce USPS Zip Code polygons, the reverse geocoding process was applied to the 16 million Tiger/Line type 'A' records to arrive at an approximation that would be independent of any errors and omissions the Tiger/Line database contains. The assumption was made that towns, cities and counties with a single zip code would be processed as that zip code.