Stephen Osborn wrote:

http://www.climbvertigo.ca/location-first-face.htm seems to indicate
that in places, the cliff is actually overhanging.

Yes but that is not vertical so the contour lines (of different
heights) would not be coincident.

I am struggling to get my mind around how an overhang should be shown
on an OS map.

It would involve contour lines crossing. Each would have to be clearly
labelled at every point.

Tim (tm)
--
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