It's a common trope of the action-thriller: A secretive government agency is tracking someone using just their cell phone. But it's not just in movies. Every few seconds, your phone is looking for the nearest cell tower, and each time it connects, your phone company knows. Pull all that data together, and you have a comprehensive way of tracking cell phone subscribers. And one German politician did just that, suing his phone company to get all the data they had collected on him. It's all been collected in a simple interactive interface at German newspaper Zeit:
That's every single movement, text, and phone call by Green Party politician Malte Spitz, collected by Deutsche Telekom. Here's Spitz on a train:
You can see the towers fading out behind him, as well as the the new, brighter towers ahead of him, picking up his signal. Zeit cross-referenced the geolocation data from the phone company with Spitz's blog and Twitter feed, and they display information about what he was doing alongside the map. You can also see when he sends a text or makes a phone call, but, keep in mind, the phone company knows where he is even when he's not using his phone in any way. The only time that he can hide from the phone company is when his phone is off. Those are the white sections below (each bar is a day):
How much data is your cell phone giving your service provider about you? The New York Times asked U.S. telecom companies how much data they collected on their subscribers. Unsurprisingly, "the major American cellphone providers declined to explain what exactly they collect and what they use it for."