busdriver wrote:Shazbat wrote:I've recently noticed that some older kerbstones round my way (West End) have letters carved into them - usually what looks like a T or a J, sometimes wee arrows. Does anyone know what these signify?
These are bench marks used by Surveyors in conjunction with information from the Ordance Survey and are used as a reference to determine heights above mean sea level.
Further information from:
http://tinyurl.com/3xpq84g
My job involves levelling (though not as much as it used to); in the 16 years I've been doing it I've never encountered a benchmark on a kerbstone.
I very much doubt that Ordnance Survey would have ever placed benchmarks on kerbstones for the simple reason that the risk of the kerbstone being moved or replaced (e.g. due to road realignment or drainage work) would be too high. Benchmarks were placed on 'permanent' structures, most commonly walls (e.g. buildings; garden walls; bridge parapets).
Vinegar Tom wrote:
The arrow in the above kerbstone is similar to the most common type (cut mark) of benchmark but it is not one. Cut marks are found on vertical surfaces and are basically an arrow pointing directly upwards with a horizontal line (which is the feature used for levelling) across the top of the arrow head. If you look closely at this
GSV image (zoom in to the top of the weed that is located below where the Coke can is sitting) you can see one that is located on the parapet of the Balmore Road bridge over the Queen Street-Anniesland rail line.