You need both: the map data (OSM project), and software for viewing/using it.
Ideally any app using OSM data would enable contributing to the underlaying map data. But that's probably not how it works.
For what it's worth: I like Organic Maps for being more lightweight, quicker rendering & simpler configuration than OSMand. But it (still? haven't used in a while) does lack some useful features like points of interest (supermarkets, gas stations & such).
Would be nice if it were easy to share (offline) map data between apps. Download in app A, backup on sd card , use from app B, C, D, or on other device by swap/copy sd card. Maybe it's possible, but I haven't figured out how (on Android). At least it's not easy/obvious/automatic.
Ideally any app using OSM data would enable contributing to the underlaying map data. But that's probably not how it works.
For what it's worth: I like Organic Maps for being more lightweight, quicker rendering & simpler configuration than OSMand. But it (still? haven't used in a while) does lack some useful features like points of interest (supermarkets, gas stations & such).
Would be nice if it were easy to share (offline) map data between apps. Download in app A, backup on sd card , use from app B, C, D, or on other device by swap/copy sd card. Maybe it's possible, but I haven't figured out how (on Android). At least it's not easy/obvious/automatic.