Lokimaps

Topo maps - Finland puts the official maps from the National Land Survey of Finland in your pocket. You get Finland-wide coverage at multiple scales, sharp Retina display, and depth data for many lakes, all offline and usable even without a signal.

Key features include full offline use—download any area, GPX import/export with folders intact, a ruler for measuring distances, location sharing, base camp markers, and address/search with recents and autocomplete. Extras add property borders in Finland, ocean maps, Topo maps for Sweden and Norway, and World topo maps powered by Thunderforest Outdoor on yearly subscriptions. Note: background GPS can drain battery on longer trips.