geocoder.us: a free US address geocoder: "New! City, State, and ZIP code Geocoding
Geocoder.us now supports geocoding on ZIP code, or city and state. Read about city/state and ZIP code geocoding. This code is in Beta status, which means it probably works, but I don't yet have the programmer courage to label it 'done.'
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Locative Technology is proud to offer licenses to use our web services for commercial or for-profit purposes.
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Interested in development-free bulk geocoding? Learn how we have taken the work out of geocoding, and then contact our data bureau at databureau@geocoder.us.
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What is geocoder.us?
Geocoding is the process of estimating a latitude and longitude for a given location. Geocoder.us is a public service providing free geocoding of addresses and intersections in the United States. The geocoding service relies on Geo::Coder::US, a Perl module available for download from the CPAN.
How does it work?
The US Census Bureau provides location data for nearly every street and highway in the US in the form of the TIGER/Line data set, which runs to over 24 gigabytes uncompressed. Geo::Coder::US condenses the 2004 TIGER/Line data set down to a 750 megabyte BerkeleyDB database. A given address or intersection is parsed into its components, and the matching address range is searched for in the database. The address is then interpolated between the endpoints of the matching address range to estimate its latitude and longitude. For urban addresses, the coordinates given by Geo::Coder::US can be within 10 or 15 meters of t"