Do you want to know where you’ve been?
There is a Nextcloud/ownCloud app to track that, and optionally share it over the internet. PhoneTrack-oc is an opensource tool/api for real-time tracking of GPS location data. It does track 3-D, so you can see your elevation changes over the course of your trek, as well as a variety of other statistics.
There are two excellent elements of this app: it has built-in support for a range of devices, simplifying building the GET-based url to the api, and allows event-based granularity for sharing, meaning you might have dozens of tracks stored in the cloud but you can pick and choose which ones are shared – either with other federated cloud users or more publicly.
Tracks are collected per-device, so you might have dozens of different devices recording and reporting their locations, each creating its own unique track (think geo-tracking unit[en.WP]) but only display one or two.
All this location information is a two-edged sword, of course – lots of applications, but the privacy risks are equally obvious. Which is why it is nice to have control of this information in your own cloud rather than on some for-profit organization’s proprietary server. Still, this particular application has some rough edges which make it a bit challenging at times to use, and the documentation thus far is particularly limited.
But it is yet another application added to our family instance of Nextcloud, and another feature I have often wanted to have available for myself.