i've never seen a trail mapped under an over hanging rock outcrop, or similar feature. e.g., in my neighborhood, the indian ladder trail in thacher park goes under overhanging rock for quite a distance. how to map this, or something like it?
Map the track as-is, and map the cliff beside it as it appears at ground level. Adjust (ie. fudge) the top so that it makes sense to a runner coming in from above, but don't map anything beyond the cliff line. Presumably there's a pretty serious drop, so mapping it as permanent OOB would be a nice way to stop people nitpicking your fieldwork. :)
It's the same problem as trying to map multi-level areas on sprint maps. You pick the most logical running level and map it, then either ignore the other levels or map them as best you can so that it makes sense to a runner.
Or, you could use a tunnel/bridge/crossing point type interpretation.
Make it a sprint map.... Canopy? ;-}
I'd be inclined to omit the trail where it is under the overhang, but show a narrow strip of white along the bottom of the cliff (if it is not otherwise white). The orienteer just needs to know if they can run along the bottom of the cliff between the two ends of the trail visible on the map, and leaving this area white shows them that they can.
At 1:15000 an impassable cliff is drawn at 0.35mm, which represents 5.25m on the ground. A footpath is drawn at 0.25mm, or 3.75m on the ground. There needs to be some space between them or they will merge on the printed map - probably at least another 0.25mm. To draw them both means nearby features will have to be displaced by 12 metres.
i am new here ,and my english is poor .who can tell me where can i get some video for orienteering training? not from TOUTOBE please, i am from china. youtobe is out of our reaching.