The term benchmark originates from chiseled horizontal marks, like this one, that surveyors made into which an angle-iron could be placed to bracket (bench) a levelling rod, thus ensuring that the levelling rod can be accurately repositioned in the same place in the future. These marks were usually highlighted with a chiseled arrow below the horizontal line.
Date
3 January 2006 (original upload date)
Source
No machine-readable source provided. Own work assumed (based on copyright claims).
Author
No machine-readable author provided. JeremyA assumed (based on copyright claims).
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