BTW, having the GPS on must have been a massive battery drain. I know it is on my phone, especially for initial triangulation. I wonder if low power mode would help?
Is there a way to toggle off the GPS on an android phone?
Not much data in or out of Google is plain http anymore.
“Google collects Android users’ locations even when location services are disabled”: https://qz.com/1131515/google-collects-android-users-locatio...
Simple example: A random user with ID 'aaa' will provide location data throughout the day. This provides you with the means to figure out where they work, how late they get up, what their average walking speed is, etc. One day the user get's a new randomID 'bbb'. At first glance there is no connection between 'aaa' and 'bbb'. But from a specific day 'aaa' stops transmitting data, and 'bbb' starts transmitting data. 'bbb' will submit the same data and thus you can figure out for example their walking speeds and place of work. This means 'aaa''s data will match 'bbb''s. Looking at the datetime when the switchover happened you could deduce that 'aaa' and 'bbb' are probably the same. With more data points you can increase your accuracy.
IE: with sufficiently large datasets (which they have), no amount of anonymization works (which they know).