Mapping North Korea in OpenStreetMap is, by necessity, an exercise in armchair mapping—i.e., drawing maps from aerial imagery and other data sources—because on-the-ground mapping is, to say the least, impractical. French OSM user Koreller has created a North Korea mapping guide for OSM contributors.¹ See Koreller’s diary entry about the guide, plus their entry about mapping the North Korean capital, Pyongyang.

1. According to a note on their user profile, the French version is the most up to date.