Updated: Never — Philip's Blog

Android-based phones use a lot of databases in the sky to determine where people are. Not only does it use tower information, it also uses information from nearby access points. Presumably, Google has a small army driving around all over the world, noting access points it finds. Maybe they're the same people who also take pictures of every building they see?

Today, my phone suddenly decided that I was in Beijing. Strange, I thought. I had no recollection of getting on a plane, the air was breathable and the people around me didn't look particularly Chinese. Indeed, there was overwhelming evidence that I was not in Beijing.

A short while later, my phone decided that I was in Brest. The one in Belarus, on the border with Poland not the one in France, or the one in Germany, both of which are at least in the same timezone as where I really am.

From Beijing to Brest in under ten minutes and yet, I don't think I went through any wormholes. In fact, I was quietly sitting at my desk near Antwerp.

Highly entertaining.

Of course, the building I'm sitting in contains an unusually high number of access points. Usually more than fifty, sometimes more than a hundred. Have Google's location soldiers been a bit too thorough collecting data near factories where wireless access points are built? Or do the databases get confused when you give them too much data? No idea. I don't think the databases or the source code used for location are publically available.

There are a number of interesting drawbacks to the phone thinking it's in the wrong location. It gets the weather (very) wrong, but I can look outside to know what the weather is like. It also helpfully adjusts the clock to its perception of local time. This would be annoying if I used Google Calendar or a similar application which (stupidly) keeps times for events local to where you add the event to your calendar, rather than local to where the event will take place. Certain websites also feel they should speak to me in a different language (and in this case, different scripts too).

Unfortunately, while you can tell the phone not to use wireless location at all, you can't tell it that you want GSM location but not WiFi location. While WiFi access points move around (possibly quite a bit) between manufacture and deployment, GSM location is a bit more deterministic.

Because the access points may move again, there's probably not much point in reporting the access points and their real location to Google. It would be much more useful to have the option to selectively disable sources of location information with more granularity.

I am realistic (cynical?) enough to know that turning location detection off probably adds zero privacy benefit to compensate for the reduced functionality (getting the right time as soon as you get off a plane, for instance) that I just leave it on.

If you're on the run for agents of an Evil Repressive Government, the first thing you need to do is ditch your mobile phone. Buy a new one (cash) if you really need to call someone. Or use a pay phone.