What Your Phone Reveals: A Guide to Location Metadata
"Metadata" sounds innocuous. Technically, it means "data about data." In the context of location surveillance, it means the comprehensive record of where you have been, how long you stayed, how you got there, who else was present, and what those patterns reveal about your life. Supreme Court Justice Sotomayor wrote in 2012 that metadata "reflects a wealth of detail about her familial, political, professional, religious, and sexual associations." Nothing has gotten less true since then.
The Six Layers of Location Metadata
Raw Coordinates
Latitude, longitude, altitude, and timestamp. The atomic unit of location data. Accurate to 3–5 meters with GPS, 10–50 meters with cell tower triangulation, 10–20 meters with Wi-Fi positioning.
Derived Activity Classification
Modern location processing pipelines automatically classify what you were doing at each coordinate: sleeping (stationary overnight at home), commuting (linear movement at transit speed), working (stationary during business hours at a non-home address), shopping (multiple brief stops at retail locations). You do not have to tell an app you were at work — your movement pattern announces it.
Place Attribution
Coordinates get matched against point-of-interest databases. The coordinate that is your doctor's office building becomes "visited a medical facility." The coordinate that is a mosque becomes "attended religious services." The coordinate that is an AA meeting becomes sensitive health data.
Social Graph Inference
When two devices occupy the same location at the same time repeatedly, they are statistically associated. A broker with both devices in their database knows you met. Aggregate this across many devices and you can reconstruct social networks from pure location data, no communication metadata required.
Behavioral Fingerprinting
Your unique pattern of home location, work location, commute route, gym, place of worship, and weekend behavior is a behavioral fingerprint as unique as a biometric. Once a broker has enough history, they can re-identify you from new data even after you reset your advertising ID.
The Practical Implication
Location metadata is not neutral. It is a high-resolution portrait of your life, compressed into coordinate pairs. Protecting it requires treating it with the same seriousness you would apply to protecting your medical records or financial data — because in the hands of a sophisticated analyst, it reveals both.