Benchmark (surveying)

:This article is about the use of benchmarks in surveying, for other uses see Benchmark

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A benchmark is a point of reference for a measurement. In surveying a benchmark is set by a surveyor to mark a point of known vertical elevation. These marks may be chiseled into a wall or they may be small brass or aluminium disks, concrete posts, iron pins or bolts that are permanently attached to a stable foundation. In all cases the mark is used by subsequent survyors to establish the elevation of nearby points.

Related Topics:
Surveying - Chisel - Brass - Aluminium

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The term benchmark originates from the chiseled horizontal marks 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 repositioned in the same place in the future. These marks were usually highlighted with a chiseled arrow below the horizontal line.

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