Ordnance Survey Bench Marks suitable as a stop?
I've just had a Ordnance Survey Bench marks (BMs) rejected as a stop as it didn't meet the criteria for a stop. Can anyone help explain why it doesn't meet the desired criteria?
Bench Marks are of historical importance as they were survey marks made by Ordnance Survey to record height above Ordnance Datum. If the exact height of one BM is known, the exact height of the next can be found by measuring the difference in heights, through a process of spirit levelling.
Bench marks are the visible manifestation of Ordnance Datum Newlyn (ODN), which is the national height system for mainland Great Britain and forms the reference frame for heights above mean sea level.
The network has had little maintenance for 30 years, but there are these marks, flush brackets and trig pillars all round the UK and interesting features to find in your own town, village or city when out playing Pokemon Go.
Admitted my picture isn't great but it's location and description is on the national database of Bench Marks.
My photo is the one scanned at 07:07. Its the same marking as the second & third picture is of a Bench Mark that has been approved in another area of the UK.