It's totally possible, I think all the apps we support can store geodata on device until its uploaded. The only thing with OwnTracks client specifically, it will delete all tracked unaploaded data from the device if you change your destination server. But it warns you about it.
Ah, of course! The Trips feature is what you're looking for. Example: I track 24/7, and then go to the Trips page, hit "Create Trip" and set datetimes for the beginning and the end of the trip. Dawarich calculates and shows route on the map, and when you save the trip, time, distance and visited countries are being calculated. Check the example:
I just don't stop tracking 24/7 on my iPhone. Some users configure Automations to start tracking when they leave their home and stop when they are back. My battery drain was 5% in the last 24 hours, and if it's too much, Dawarich supports half dozen 3rd party mobile apps to track geodata (including Traccar), you can try them all :)
You can import Google Timeline data, extracted via Takeout or from your phone, GPX, GeoJSON, .rec (OwnTracks' format), KML and KMZ, so if you have some existing data, we got you covered. On iOS, there is also an option to import GPX tracks from your Apple Health, but this is a paid feature for self-hosters. It's available for free for our cloud subscribers though.
As for the whys: It's good to have a way to see where you've been at some point in time or when you visited a certain place. It's also useful for reimbursement purposes, for example I use it to see how many days I worked from home and how many days I went to fork from the office, so I could properly file my tax report and get tax reimbursement. Or to get reimbursement from my employer for a business trip
Well, Google killed their Timeline and I just dove into selfhosting at the moment, so I used OwnTracks for 6 months and decided it's not enough :) That's how Dawarich was born
F-Droid is possible but we're currently using google services for location tracking, so it's not possible to publish there due to that. And we also have a LOT of work ahead of us, so it's not a priority
Before building Dawarich, I naturally extracted my data via Google Takeout and my mind was blown same as yours when I realized just HOW MUCH they know about me even when we're talking location only. It was a big incentive for me to take control over my data, or, at least, to ALSO have it, same as many-many cloud provides and apps have.
It's totally possible, I think all the apps we support can store geodata on device until its uploaded. The only thing with OwnTracks client specifically, it will delete all tracked unaploaded data from the device if you change your destination server. But it warns you about it.