The paths around Vesuvius are quite extensive, but poorly documented, especially in terms of available GPS traces. I visit regularly, and after several attempts at reconnaissance, I've decoded most of the path network and ran it (all paths except a smaller one on the East of the mountain that's harder for me to get to and is not connected up in a way that I can decode) to get GPS traces. Today I finished the final path that I hadn't run (in the dark).
The National Park invested a lot in these paths about 10 years ago, but they seem to have been left to decay since the financial crisis. There is a lot of maintenance (tree cutting) that has not been done on the Monte Somma trail. However, they are all still very useable and putting the paths on OpenStreetMaps seemed to be the best way to make this information available. I've put the paths in, modifying the existing information where necessary. I've also added areas of woodland (they are a bit rough and ready at the moment), the cliffs of Monte Somma, the lava flow of 1944 and various buildings. I think the result is a fairly usable trekking map of Vesuvius ... certainly the most usable electronic version I've found.
One word of warning: there are several gates at the trail heads, and everytime I've been up their they've been closed. You can normally duck around them, but there is one, at the lower end of Trail 4 is closed and has a high fence either side for some distance. I only managed to duck under the fence by crawling like a rabbit (only on my back rather than front) about 100 yards up the road. I've marked the position with this diary entry location.
I'm sure I'll continue to visit and edit the map, but in the meantime I hope people get some benefit out of it. I certainly enjoyed running the trails!