Our sister publication Techcrunch UK noticed that a Location services API had been added to Google Gears. The developers behind Gears have been plotting out future API additions for a while, and those plans have included having Geo-data available to mobile app developers (see the spec here). We found out today that Google is backing up their Location API with a large effort to map out cell-phone towers and wifi hotspots, so that a user’s location can be pin-pointed more precisely.
While some cell-phones have an internal GPS, the data is inaccurate indoors and not available on all devices. The other non-GPS method for accurate location data is to use the location of cell towers. Google can store the lat and long of a particular cell tower in their database, and when their software in the future sees that cell tower on a phone, they know exactly where the phone is. To boot-strap the database, both Google and Apple have been using a company called Skyhook, who drive around pin-pointing the location of cell towers. By using this method Google bypasses the need to have deals in place with network providers for positioning data. In addition to cell-phone towers, Google is also mapping out Wifi locations to form a large rogue base station almanac, which is used for both additional accuracy in location calculations, and also to point users to the nearest available access point.
Once the database has been boot-strapped with initial data and launched to developers via an API, users of the service will further refine and improve the service by having devices submit information on towers and signal strength (along with location) back to Google. This means that over time, the service improves itself and will be able to work almost anywhere in the world, regardless of local regulations, network providers or restrictions.
It is expected that the service and associated data will be made available for free to developers using Google Gears (specifically the new Windows Mobile version). For developers of mobile applications, it means that they now have a very accurate way of not only calculating a users position, but also an easy way to pinpoint other locations as a basis for a location-based service. There is also an effort to develop and define a standard API for accessing Location data and services in the browser. As with local browser storage, Google are leading the way here by implementing first and then working with other browser developers on a standard.