How can I see what data Google has on me?

To see some of the information in your Location History, you can look at your timeline. This map of your travels does not include all of your Sensorvault data, however.

Raw location data from mobile devices can be messy and sometimes incorrect. But computers can make good guesses about your likely path, and about which locations are most important. This is what you see on your timeline. To review all of your Location History, you can download your data from Google. To do that, go to Takeout.Google.com and select Location History. You can follow a similar procedure to download your Web & App Activity on that page.

Your Location History data will appear in computer code. If you can’t read code, you can select the “JSON” format and put the file into a text editor to see what it looks like.

Can I disable the data collection?

Yes. The process varies depending on whether you are on a phone or computer. In its Help Center , Google provides instructions on disabling or deleting Location History and Web & App Activity.

How is law enforcement using the data?

For years, police detectives have given Google warrants seeking location data tied to specific users’ accounts.

But the new warrants, often called “geofence” requests, instead specify an area near a crime. Google looks in Sensorvault for any devices that were there at the right time and provides that information to the police.

Google first labels the devices with anonymous ID numbers, and detectives look at locations and movement patterns to see if any appear relevant to the crime. Once they narrow the field to a few devices, Google reveals information such as names and email addresses.