NerdTrack records your location in a CSV file on your phone.
No other data is collected and no data ever leaves your device.
Full source is available at https://nerdtrack.org

There is no interactive UI. Just grant location permissions, and it will log in the background.
To stop logging, remove location permissions or uninstall app.

The app uses the SignificantLocation API. The accuracy is low but it has very low battery usage.

To get your log, open the Files app, and look for locations.csv in the Nerd Track folder.

A config file will be created in the app's documents folder the first time it runs.
Edit that file to change logging frequency or minimal distance. Force-stop and restart app to reload config.

By default, the app records location:
- Every 15 minutes, if you have moved more than 300 meters

The CSV logs timestamps in the unix epoch format.
Use 'dateconv -i %s' to convert it to something more human-readable.
Some helper scripts are available at https://nerdtrack.org