Probably from network calls (DNS and HTTPS). An easy one is to provide a mobile hotspot with the name `attwifi` with no password and just sniff the data. You c

Probably from network calls (DNS and HTTPS). An easy one is to provide a mobile hotspot with the name `attwifi` with no password and just sniff the data. You can derive a lot of data just from the network activity on a phone and since you're on WiFi, you can get approximate WiFi location. A couple of dozen laptops in a couple of buildings and you can also approximate the direction the phones moved as they go from device to device.