Are there any better geolocation databases / technologies / services or has anyone done any work with improving the accuracy of existing systems?

Question

I am working on integrating geolocation services into a website and the best source of data I've found so far is MaxMind's GeoIP API with GeoLite City data. Even this data seems to often be questionable though. For example, I am located in downtown Palo Alto, but it locates my IP as being in Portola Valley, which is about 7 miles away. Palo Alto has a population of 60k+, whereas Portola Valley has a population of less than 5k. I would think if you see an IP originating somewhere around there it would make more sense to assume it was coming from the highly populated city, not the tiny one. I've also had it locate Palo Alto IPs completely across the country in Kentucky, etc.

Does anyone know of any better sources of data, or any tools/technologies/efforts to improve the accuracy of geolocation efforts? Commercial solutions are fine.

Answer 1

I am not sure if this will help, but here is a site that has done a pretty good job of IP mapping. Maybe you could ask them for help :) seomoz.org

Answer 2

Where an IP comes up at the wrong end of the country, you probably won't find a better match elsewhere because it's probably an ISP that uses one group of IPs for customers in a wide area. My favourite example is trains here in the UK where the on-board wifi is identified as being in Sweden because they use a satellite connection to an ISP in Sweden.

A commercial supplier may be able to afford to spend more time tracking down the hard cases, but in many cases there just won't be a good answer to give you. They may, however, give you a confidence factor to tell you when they're guessing. I've heard good things about Quova, though I've never used them.

Assuming that you've got the best latitude and longitude that you can get (or can afford), then you're left dealing with cases where they pick the closest city rather than a more likely larger city nearby. Unfortunately I don't have the code to hand, but I had some success using the data from geonames to pick a "sensible" city near a point. They list lat/long and population, so you can do something like

ORDER BY ( Distance / LOG( Population ) )

You'd need to experiment with that to get something with the right level of bias towards larger cities, but I had it working quite nicely taking the centre of a Google Maps view and displaying a heading like "Showing results near London..." that changed as you moved the map.

Answer 3

A couple of sites I saw referenced recently for free GeoIP services are

WIPmania

hostip.info