Geocode database

Question

Hi, Can I download address,city,state,postalcode - latitude/longitude information, that can be loaded to a db for US alone.. Also do comment about their accuracy and coverage..

I suppose all GPS devices do this.. any pointers where I can extract this info??

I tried google maps json api.. and don't like the idea that they rate limit the number of requests per second..

Thanks, Ramya

Edit: What I am looking for is "address , city , state , postalcode, latitude/longitude" in csv or dump.. that I can query locally.. ofcourse.. free of cost (non commercial).

Answer 1

You're looking for something like geocoder.us?

There's also the Virtual Earth API.

Here's a nice list of other geocoder services (thanks to Christopher Klein in the comments ;-)

Edit: I don't think an online service exists that will allow unlimited requests, as this is a security measure to avoid DOS attacks and the likes...

Answer 2

I've used ZipCodeDownload in the past, and it's got lat/long info as well as postal codes, cities, etc... It is a commercial product however. (note I do not, nor have I ever, worked for this company)

EDIT: It seems unlikely that you will find a free service that provides unlimited requests per second. I don't know if you looked at this link, but the product starts at $30 USD, which, in my mind is quite affordable.

Answer 3

I use the Google Maps API...

http://code.google.com/apis/maps/documentation/geocoding/index.html

every service will throttle your requests. I've found I can make continuous requests by sleeping for 200 ms in between each request (with the occasional extra sleep cycle if it's still too fast).

Answer 4

You will probably need to find several geocoding services and write your own wrapper class that uses an algorithm to select which one to use, how to use it, and how often to use it. Be careful with this though, for example, I believe that Google requires you to show the geocoding results on a Google map (can't find the reference right this moment).

In addition to Google and the others mentioned in this thread, here are a few services you could look into:

http://developer.yahoo.com/maps/rest/V1/geocode.html

http://www.maxmind.com

Answer 5

Try Geoname. If I remember well you can download the full database or use its API. Free of charge. It's an open project. Hope this helps,

X.

Answer 6

On the GeoNames you could download full database or the extracts for the country http://download.geonames.org/export/dump/

Answer 7

Check out http://www.geocodesource.com Saved me a lot of time and money.