An alternative is the Overland app for iOs [1] or Android [2], logging to compass [3]
Each has features that the other doesn't: OwnTracks can apparently determine a location using iBeacons, whereas Overland can't (though it can detect WiFi networks). Overland lets you record your mode of travel (e.g., driving, cycling, walking), whereas this still seems to be an unimplemented "idea" for OwnTracks [4]. Compass is also designed for tracking a single person, whereas OwnTrack can handle multiple.
I recently added support for it to my blog (which uses twyne.rtfd.io) so I could more easily geolocate photos (from my non-GPS camera), and it was pretty easy to integrate. I tried GPSLogger too, but found that battery life was much better with Overland, and it also has a better system of queuing points when offline (with GPSLogger I found that it lost data at times such as when there was an internet connection but the server wasn't responding).
What does determining a location via iBeacons mean? If overland is using the iOS API to determine the location, shouldn’t it also use Bluetooth and the likes (which would include iBeacons in my understanding).
It's a bit more in the user's hand. You could put a beacon in your garage and one in your kitchen and send different events with OwnTracks depending on which one is close. It's a bit more granular and hyperlocal than iOS' location API.
iOS apps can’t detect nearby access points, otherwise every app would be doing that; user location is valuable data to sell.
Apple applies a set of measures designed to make sure an app can only detect the users location if it has opt-in permission and if it is using Apples location services so they can control it. And if someone finds a way around it they might find it blocked in the next update.
Each has features that the other doesn't: OwnTracks can apparently determine a location using iBeacons, whereas Overland can't (though it can detect WiFi networks). Overland lets you record your mode of travel (e.g., driving, cycling, walking), whereas this still seems to be an unimplemented "idea" for OwnTracks [4]. Compass is also designed for tracking a single person, whereas OwnTrack can handle multiple.
[1]: https://github.com/aaronpk/Overland-iOS
[2]: https://github.com/OpenHumans/overland_android
[3]: https://github.com/aaronpk/Compass
[4]: https://owntracks.org/booklet/ideas/