I spent a week in Torsnes outside Fredrikstad this summer,
exploring the last bits of trails in Heiefjella and Thorsø-tangene.
I've traced footpaths based on over 30 tracklogs collected while mountain biking
there over the last three years.
The amazing aspect of user contributed maps is how accurate and
up-to-date we can make them. This spring they released a brand new map
of the area called "kulturhistorisk turkart" (historical hiking map).
The mapper obviously haven't revisited any of the trails recently (last 5-10 years),
as some tracks (what would have been tagged tracktype=grade4) are now
been overgrown by vegetation, and are hardly visible.
I also added woods for Torsnes, drawn after Landsat imagery and
corrected near GPS tracks of roads and trails, as well as from
memory of what the terrain looks like.