There are the openstreetmap mapping apps (OSMand, organic maps)
Organic maps should be used instead of OSMand, https://news.ycombinator.com/item?id=42343121
Or maybe Comaps, https://news.ycombinator.com/item?id=43961908
Organic maps should be used instead of OSMand, https://news.ycombinator.com/item?id=42343121
Or maybe Comaps, https://news.ycombinator.com/item?id=43961908