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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 ...
In the U.S., some survey markers have the latitude and longitude of the station mark, a listing of any reference marks (with their distance and bearing from the station mark), and a narrative (which is updated over the years) describing other reference features (e.g., buildings, roadways, trees, or fire hydrants) and the distance and/or ...
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 ...
NGVD29 was superseded by the North American Vertical Datum of 1988 , [3] based upon reference to a single benchmark (referenced to the new International Great Lakes Datum of 1985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]
A benchmark is usually set on the side, marked with the letters "O S B M" (Ordnance Survey Bench Mark) and the reference number of the trig point on a plaque called a "flush plate". Within and below the visible trig point, there are concealed reference marks whose National Grid References are precisely known.
The United States Geological Survey National Volcanic Threat Assessment is a report containing a ranked list of active volcanoes in the United States posing hazardous risks to the American population. [1] The report was published by the United States Geological Survey in 2005 [2] and revised in 2018. [3]
USGS researchers publish the results of their science in a variety of ways, including peer-reviewed scientific journals as well as in one of a variety of USGS Report Series [36] that include preliminary results, maps, data, and final results. A complete catalog of all USGS publications is available from the USGS Publications Warehouse.
The United States Geological Survey Library (USGS Library) is a program within the United States Geological Survey (USGS), a scientific bureau within the Department of Interior of the United States government. The USGS operates as a fact-finding research organization with limited regulatory responsibility.