Google announced on Tuesday that mobile phone and some laptop users who use Google applications to get a fix on their position or share their location with friends are helping Google build out a massive database of WiFi hot spots. Google quietly uses the method to crowdsource location data by matching WiFi hot spot location data with GPS coordinates by transmitting the location of any WiFi access point in wireless range.
Most Google apps, in essence, turn your phone into a Google WiFi sensor, and even laptop owners using browsers that take advantage of HTML5 geolocation technologies are also contributing to the database when they divulge their location to services like Twitter or Foursquare, or use Firefox geolocation services for example. When that data gets sent back to Firefox, it shares the location of all MAC addresses in range with Google for mapping and other purposes.
When a Google Maps Navigation user, for example, requests a fix on their location, they send Google a list of all the MAC (media access control) addresses associated with wireless hot spots available within range to be checked against a Google database of those addresses gathered through the Street View project, said Steve Lee, group product manager at Google. WiFi hot spot triangulation is a commonly used method of determining location on modern smartphones, as GPS doesn’t always work in urban locations and cell-tower positioning can be inaccurate.
The location data sent to Google is anonymous and users can decline to send the data back to Google, Lee said. However, if you decline to send anonymous location data to Google you’re not allowed to use a wireless network to triangulate your position, so the company is saying you either help us collect data or fall back on GPS or cell-tower positioning to find out where you are. While it may sound like a privacy nightmare, the concept is actually advantageous to all mobile users. It differs greatly from the Street View fiasco that has prompted Google to completely suspend its vehicles until privacy implications can be worked out.