Google services on Android devices and iPhones store your location data even if you've used privacy settings that say they will prevent it from doing so.
According to an Associated Press investigation, confirmed by computer-science researchers at Princeton, Google is upfront about asking permission to use your location information. An app like Google Maps will remind you to allow access to location if you use it for navigating. If you agree to let it record your location over time, Google Maps will display that history for you in a "timeline" that maps out your daily movements.
Storing your minute-by-minute travels carries privacy risks and has been used by police to determine the location of suspects - such as a warrant that police in Raleigh, North Carolina, served on Google last year to find devices near a murder scene. So the company will let you "pause" a setting called Location History.
Google says that will prevent the company from remembering where you've been. Google's support page on the subject states: "You can turn off Location History at any time. With Location History off, the places you go are no longer stored."
But the research found that even with Location History paused, some Google apps automatically store time-stamped location data without asking.
For example, Google stores a snapshot of where you are when you merely open its Maps app. Automatic daily weather updates on Android phones pinpoint roughly where you are. And some searches that have nothing to do with location, like "chocolate chip cookies," or "kids science kits," pinpoint your precise latitude and longitude - accurate to the square foot - and save it to your Google account.
The privacy issue affects the billion of users of devices that run Google's Android operating software and hundreds of millions of worldwide iPhone users who rely on Google for maps or search.
Google says everything is clear.
"There are a number of different ways that Google may use location to improve people's experience, including: Location History, Web and App Activity, and through device-level Location Services," a Google spokesperson said in a statement to the AP. "We provide clear descriptions of these tools, and robust controls so people can turn them on or off, and delete their histories at any time."
To stop Google from saving these location markers, the company says, users can turn off another setting, one that does not specifically reference location information. Called "Web and App Activity" and enabled by default, that setting stores a variety of information from Google apps and websites to your Google account.
When paused, it will prevent activity on any device from being saved to your account. But leaving "Web & App Activity" on and turning "Location History" off only prevents Google from adding your movements to the "timeline," its visualization of your daily travels. It does not stop Google's collection of other location markers.
You can see the stored location markers on a page in your Google account at myactivity.google.com, although they're typically scattered under several different headers, many of which are unrelated to location.
Tracking Google's users' locations stems from its drive to boost advertising revenue.
Google clearly states that location records stored in My Activity are used to target ads. Ad buyers can target ads to specific locations and typically have to pay more to reach this narrower audience.
While disabling "Web & App Activity" will stop Google from storing location markers, it also prevents Google from storing information generated by searches and other activity. That can limit the effectiveness of the Google Assistant.