It has been requested a few times to build a version of this app that uses OpenStreetMap instead of Google Maps - which would then be fully open source and suitable for inclusion in F-Droid. It would also be able to run on Android devices without Google Play Services (e.g. custom ROMs).
In principle, I would like this to happen, but it causes a few problems:
- OSM data are free, but hosting is not
- Freely available tile servers have strict usage policies, e.g. OSM themselves do not allow distributing apps that use their tile server. I haven't found a usage policy for Carto basemaps, which e.g. wo-ist-markt seems to be using.
- Commercial tile providers like Mapbox and MapTiler have free plans, but only up to a certain limit.
- GoingElectric.de is also hosting OSM tiles themselves. They seem to be available using the same API keys as the GE charging stations API, but this is not documented anywhere and therefore probably not intended to be used by external applications.
- We could host map tiles ourselves, but this is costly due to the high hardware requirements.
- Google Maps, on the other hand, is currently free for all Android Apps without any usage limits.
- Google Maps provides some features which are not easily replacable with OSM data (satellite images, traffic data). These would then not be available in the app anymore.
- Maps is not the only thing in the app which uses Google services. Place search ("geocoding") would also need to be replaced, and APIs for this cost money as well.
Additionally, we would need to replace Fused Location Provider API and Google Play In-App purchases, but that would not be very complicated.
- I wouldn't want to completely replace Google Maps, but instead offer both Google Maps and OSM in parallel. But this would also difficult to maintain due to the completely different APIs of Google Maps and osmdroid. https://github.com/sharenowTech/AnyMaps looks a possible solution, but it seems to not be actively maintained anymore.
Because of all these issues, I will not actively work on this at the moment. If someone is interested, feel free to search solutions to these problems and start a PR.