geocoder.us

(and now also geocoder.net)

find the latitude & longitude of any US address - for free

Apr 22, 2008 Note: See Using Geocoder.us for Address Parsing for information on using the geocoder to parse US addresses.
Sept 17, 2007 Note: I added http://geocoder.us/mobile.html as an ultralightweight address lookup. Try it on your mobile device. Let me know Rich@geocoder.us how it works for you.

Read the NEW Geocoder.US Blog

The new Blog is the place to look for what is happening with Geocoder.us.

Recent Blog Entries:

How to calculate the distance between two points

Degrees, Minutes, Seconds? Decimal Degrees? Huh?

Added display of coordinates in Degree-Minute-Seconds form in demo.cgi

How many digits are enough? 38.2? 38.23? 38.234? How many digits of precision do we need?

This material is Open Knowledge "A piece of knowledge is open if you are free to use, reuse, and redistribute it". For details read the latest version of the full definition . (sort of like the Make motto 'if you can't open it, you don't own it.') You are free to use the Geocoder.US code and the data is free from the US government (if you want to use our servers for commercial purposes please sign up for a commercial account :-)

Ideas on using Geocoder.us

Gallery of users of Geocoder.us If you want your application listed email contact@geocoder.us.

Calculating Distances (new Jan 30, 2008)

Geocoder.us now supports Calculating distances

either (lat,lng) to (lat,lng) or provide zip codes! I invite feedback on how to make this more useful (for example, returning the distance in JSON). Please send me feedback. databureau@geocoder.us

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.'

Commercial Services!

Locative Technology is proud to offer licenses to use our web services for commercial or for-profit purposes.

Web Services Interface

Sign up for an account
Purchase 20,000 lookups for $50 (bulk geocoding has a $50 minimum, web service use has no minimum)
Read the Documentation to Integrate your application (for both the free and pay services)
Log in to see your account status
Request a new password

Interested in development-free bulk geocoding?

Bulk Geocoding

Send us data
We geocode it, and return it to you
if you like it, pay for it! The cost is $50 per 20,000 records with a $50 minimum.
Please read this description of the process

Read more about how we have taken the work out of geocoding, and then contact our data bureau at databureau@geocoder.us.

Affordable for many different applications!

Get 4 lookups per 1¢!

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 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!

Datum and Projection

From the Tiger Metadata "NAD83 is the coordinate datum used for the 48 contiguous states, the District of Columbia, Alaska, Puerto Rico, and the Virgin Islands of the United States. Regional datums are used for Hawaii and the Pacific Island Areas."

And

"The TIGER/Line data are not in a mapping projection even though most of the features were scanned directly from source maps (usually USGS 1:100,000-scale topographic quads) that were in a projection."

Read the metadata yourself to get a better understanding of what this means for your applications, and to get a feel for the magnitude of the task that the Census did (rah, rah, go census!).

Is it really free?

You bet it is! Commercial US geocoding services can charge up to $1 per lookup, but the TIGER/Line data on which their geocoders (and ours) are based is in the public domain. The Geo::Coder::US suite is made available free for download under either the GPL v2 or the Perl Artistic License. All data from the free services on the geocoder.us website are provided under a NonCommercial-ShareAlike license, which means you can use anything you get from us for any non-commercial purpose, so long as you give us proper credit and extend the same courtesy to others.

See the geocoder in action!

Enter a US address or intersection, e.g. 1600 Pennsylvania Ave, Washington, DC. You must include a city and state or a ZIP code.

Try one of these examples...

For best results please use a comma between the street and the city, and add the zip code if possible.

How can I help?

You can make improvements to the source code and send patches for inclusion in future releases. You can also donate via PayPal to help defray the cost of developing and hosting this free public service. Any amount is appreciated!

Where do the maps come from?

All of the maps you see on this website are generated by the US Census Bureau's TIGER Mapsurfer, and are in the public domain. They are based on the 1998 TIGER/Line data set, so they may be a little out of date. You can find how to include their maps on your own website from the Census Bureau's TIGER Mapping Service instruction page. The geocoding results are generated using the most recent (or at least close) Tiger data set.

The geocoder can't find my address!

Well, the TIGER/Line data set is notoriously incomplete, but there may be bugs in Geo::Coder::US that prevent it from finding particular addresses or intersections. However, we continually try to improve the quality of our service.

Please send an e-mail to missing@geocoder.us if our geocoder can't find an address that you're sure exists, so that we can refine and improve our code.

How can I make my own geocoder?

You can download the code and the latest TIGER/Line data, and build your own Geo::Coder::US service or application for whatever purpose you like.

How can I use it?

You may use the demo on this website for non-commercial purposes.

We encourage you to write code using our web services API for non-commercial purposes! You can read our developer documentation, and take a look at some example SOAP, XML-RPC, REST-ful RDF, and NEW REST-ful CSV (plain text) clients. Please drop an email to services@geocoder.us if you plan to build our web services into your application, so that we can keep you informed of service updates or changes. We intend to make every effort to keep the geocoder running stably, but this service is provided with no warranty or guarantee of availability!

If you wish to use our web services for commercial purposes, you must sign up for a commercial license, or contact us to discuss other options. Please see our Terms and Conditions of Service for more details.