How Google - and everyone else - gets wi-fi location data

"Summary:  Google doesn’t use StreetView cars to pick up Wi-Fi location data any more. They use your smartphones and tablets instead...

"So, how does Google collect Wi-Fi location data? They use you.

"Or, to be more exact, they use your Android phone or tablet. But, it’s not just Google. Apple and Microsoft do the same thing with their smartphones and tablets...

"How it works, according to Google, is that the Android Location Services periodically checks on your location using GPS, Cell-ID, and Wi-Fi to locate your device. When it does this, your Android phone will send back publicly broadcast Wi-Fi access points’ Service set identifier (SSID) and Media Access Control (MAC) data. Again, this isn’t just how Google does it; it’s how everyone does it. It’s Industry practice for location database vendors.

"Google tells me that the location checks are made periodically. You don’t need to be using Google Maps, Latitude or other geolocation-based application. It just happens.

"You can check on this yourself by going to your Android phone and then going to Settings/Location and check Google Location Services or Security/Use Wireless Network off and on. When you check it on you’ll get a location consent agreement. This reads: “Allow Google’s location service to collect anonymous location data. Collection will occur even when no applications are running.”

"You don’t have to use Google’s Wi-Fi location service. You can elect to just use your device’s built-in GPS, but the more data points your smartphone has to work with the more accurately it can fix your location and thus make location-based services more accurate and useful. In other words, if you use Wi-Fi on an Android device to help pin your position down though you’ll also be contributing to creating Google’s maps.

"If all that makes you feel a little queasy-what is Apple, Google, and Microsoft doing with this information–well each of them states that they’re using the data anonymously...

"Still don’t trust them? Well, you can always write your Congress-critter and ask them to support the GPS act, which is meant to set guidelines, legal procedures and protections on electronic devices and location tracking. Specifically it states that the

• Government must show probable cause and warrant to acquire geolocational information.
• The Act will apply to real-time tracking of person’s current and past movements.
• Creates criminal penalties for using a device to track a person.
• Prohibits commercial service providers from sharing geolocation data with outside entities.

"The GPS act still hasn’t passed into law, but it’s slowly drawing broader support.

"In the meantime, if you’re really that concerned about the possibility of your phone being tracked, then just don’t use Wi-Fi or cellular services on your Android phone, or any other device, to help fix your location. On my Droid 2 phone with Android 2.3, the option to do this is Setting/Location & Security settings/Standalone GPS services..."

ZDNet