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Marcus P. Zillman, M.S., A.M.H.A. Author/Speaker/Consultant
Marcus P. Zillman, M.S., A.M.H.A. Author/Speaker/Consultant Internet Happenings, Events and Sources
Saturday, February 25, 2006
geocoder.us
geocoder.us - Find the Latitude and Longitude Of Any US Address - For Free http://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 the actual location -- which is well within the range of typical GPS accuracy! Other times the coordinates can be off, so use your own judgement when using the data! This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.
posted by Marcus Zillman |
4:15 AM
