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Benchmarking, also known as benchmark hunting, [1] is a hobby activity in which participants find benchmarks (also known as survey markers or geodetic control points). The term "benchmark" is used only to refer to survey markers that designate a certain elevation , but hobbyists often use the term benchmarks to include triangulation stations or ...
Survey markers, also called survey marks, survey monuments, or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying . A benchmark is a type of survey marker that indicates elevation ( vertical position ).
An Ordnance Survey cut mark in the UK Occasionally a non-vertical face, and a slightly different mark, was used. The term benchmark, bench mark, or survey benchmark originates from the chiseled horizontal marks that surveyors made in stone structures, into which an angle iron could be placed to form a "bench" for a leveling rod, thus ensuring that a leveling rod could be accurately ...
It traces its history to the Survey of the Coast, which was formed in 1807 as the first scientific agency of the U.S. federal government. It became the United States Coast Survey in 1836 and the United States Coast and Geodetic Survey in 1878, the latter name change reflecting the increasing role of geodesy in its work. Upon the creation of ...
NGVD29 was superseded by the North American Vertical Datum of 1988 , [3] based upon reference to a single benchmark (referenced to the new International Great Lakes Datum of 1985 local mean sea level height value), although many cities and U.S. Army Corps of Engineers "legacy" projects with established data continued to use the older datum. [4]
The surveyor would also obtain copies of deed descriptions and maps of the adjoining properties, any records from the municipality or county, utility maps, and any records of surveys. Depending on which region the survey is located in, records may be incomplete or difficult to find. A thorough search is important so that no records are overlooked.
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Electronic distance measurement (EDM) was introduced around 1960, when the prototype instruments became small enough to be used in the field. Instead of using only sparse and much less accurate distance measurements some control networks were established or updated by using trilateration more accurate distance measurements than was previously possible and no angle measurements.