Benchmark (surveying)

An Ordnance Survey cut mark in the UK
Occasionally a non-vertical face, and a slightly different mark, was used
An Ordnance Survey flush bracket
C&GS benchmark disk in the United States
Bench mark at Saint Goussaud, Limousin, France, by Institut Géographique National
City of Toronto benchmark disk in Canada
Benchmark disk in Ottawa, Ontario, Canada
Vial Moll de Bosch i Alsina, near Port de Barcelona building, & pedestrian crossing Barcelona
Benchmark on the plinth of the statue of King Charles I in Trafalgar Square, London: the site of the medieval Charing Cross, and the point from which distances from London are calculated
Benchmark painted on an electricity pylon's foundation
Benchmark of the Prussian Survey Authority on a church in Brandenburg

Angle-iron could be placed to form a "bench" for a leveling rod, thus ensuring that a leveling rod could be accurately repositioned in the same place in the future.

- Benchmark (surveying)
An Ordnance Survey cut mark in the UK

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A trigonometrical station in Hong Kong

Triangulation station

Fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity.

Fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity.

A trigonometrical station in Hong Kong
The triangulation point on top of Mount Washington in New Hampshire
A geodetic survey marker in Wellington, New Zealand
Class 3 triangulation point in Shiroyama Park in Inagi, Tokyo
Trig beacon on the summit of Lion's Head in Cape Town
A triangulation pillar in Torre del Miguelete. Valencia (Spain)
A trig point near Wootton Wawen, Warwickshire, England
Trig point on Mam Tor, Derbyshire, England
Trigonometrical station, NSW, Australia.

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.

Spot height 479 near Arenig Fach in Snowdonia, Wales, marked by a cairn

Spot height

Exact point on a map with an elevation recorded beside it that represents its height above a given datum.

Exact point on a map with an elevation recorded beside it that represents its height above a given datum.

Spot height 479 near Arenig Fach in Snowdonia, Wales, marked by a cairn

Unlike a bench-mark, which is marked by a disc or plate, there is no official indication of a spot height on the ground although, in open country, spot heights may sometimes be marked by cairns.

A stylised broad arrow

Broad arrow

Variant, is a stylised representation of a metal arrowhead, comprising a tang and two barbs meeting at a point.

Variant, is a stylised representation of a metal arrowhead, comprising a tang and two barbs meeting at a point.

A stylised broad arrow
Heraldic broad arrow with plain barbs
Pheon in the arms of the Sidney family of Penshurst: Or, a pheon azure
Ammunition box dated 1831, displaying Board of Ordnance coat of arms, initials and broad arrow
British convicts in uniforms bearing broad arrows: a late 19th-century print
A broad arrow on a Marconi TF1041B valve voltmeter, indicating Ministry of Defence ownership
An Ordnance Survey benchmark in the UK
War Department Ordnance Survey marker, Bermuda
Benchmark of c.1829 on the line of the Great North Road, Sydney, Australia
Registration plate of an Indian military vehicle

Topped with a horizontal line, the broad arrow was widely used on Ordnance Survey benchmarks.

Example of a surveying expedition in the 20th Century similar to those undertaken to complete the Australian Height Datum.

Australian Height Datum

Example of a surveying expedition in the 20th Century similar to those undertaken to complete the Australian Height Datum.
An old tide gauge positioned at Fort Dension, Sydney, Australia
This map illustrates the positions of the 30 tide gauges used in the determination of the Australian Height Datum (mainland)

The Australian Height Datum was introduced in 1971 as the official vertical datum for Australia, and thereby serves as the benchmark to which all height measurements are referred.

Westchester County, New York

Located in the U.S. state of New York.

Located in the U.S. state of New York.

Harbors, islands and shoreline of New Rochelle
Philipsburg Manor House in Sleepy Hollow
The New Croton Reservoir is the largest of many in the county.
Municipalities in Westchester County, New York
Philipse Manor Hall in Yonkers
Tarrytown Music Hall on Main Street
The Tappan Zee Bridge connecting Tarrytown to South Nyack
Westchester County Airport near White Plains
The Old Dutch Church in Sleepy Hollow

At 987 feet, the highest elevation in the county is a U.S. Coast and Geodetic Survey benchmark known as "Bailey" in Mountain Lakes Park near the Connecticut state line.

Temiskaming Shores

City in the Timiskaming District in Northeastern Ontario, Canada.

City in the Timiskaming District in Northeastern Ontario, Canada.

Riverside Drive
Haileybury, 1915
Old narrow gauge train at Haileybury, 1889
Haileybury after its destruction in the Great Fire of 1922.
retired street cars
Timiskaming Square
Haileybury
New Liskeard
North Cobalt

A benchmark near Mattawa was used to establish an accurate benchmark north of Lake Timiskaming, using astronomical methods.

A person taking a photo of a located benchmark

Benchmarking (hobby)

A person taking a photo of a located benchmark
A typical USCGS Benchmark
Typical Metal Rod or Stake Benchmark
Benchmark at Saint Goussaud, Limousin, France, by Institut Géographique National
Vial Moll de Bosch i Alsina, near Port de Barcelona building, & pedestrian crossing Barcelona
An Ordnance Survey flush bracket in the UK

Benchmarking, also known as benchmark hunting, is a hobby activity in which participants find benchmarks (also known as survey markers or geodetic control points).

Albany, New York

Capital of the U.S. state of New York, and the seat and largest city of Albany County.

Capital of the U.S. state of New York, and the seat and largest city of Albany County.

North Pearl Street from Maiden Lane North by James Eights, circa 1805
This 1895 map of Albany shows the gridded block system as it expanded around the former turnpikes.
The steamer Albany departs for New York City; at the height of steam travel in 1884, more than 1.5 million passengers took the trip.
The Albany Lumber District was home to the largest lumber market in the nation in 1865.
Broadway in Albany during the funeral ceremonies for Abraham Lincoln (1865)
The Albany Institute of History & Art
This 1955 map shows the planned expansion of the Interstate Highway System around Albany.
The Albany Pine Bush is the only sizable inland pine barrens sand dune ecosystem in the United States.
Housing in Ten Broeck Triangle, a subset of the Arbor Hill neighborhood
The 1929 Washington Park Lake House replaced a wooden lake house built in 1876.
Lincoln Park is flanked on the north by the Empire State Plaza.
The New York State Capitol
Aerial view of Albany looking northeast
System Administration Building of the State University of New York
This 1789 etching shows the Dutch influence on the architecture of early Albany.
Price Chopper sponsors the annual Fourth of July fireworks show at the Empire State Plaza (2009 show pictured).
An artist paints tulips during the Tulip Fest at Washington Park.
Ten Broeck Mansion is home to the Albany County Historical Association.
Southwest corner of the Cultural Education Center on Empire State Plaza housing the State Museum, Library, and Archives.
Albany High School is the central high school of the City School District of Albany.
State Quad is one of the four iconic dormitory towers at SUNY Albany's Uptown Campus.
One Commerce Plaza
SUNY Polytechnic Institute's College of Nanoscale Science and Engineering embodies Albany's emerging high-tech industry.
Albany City Hall, an 1883 Richardsonian Romanesque structure, is the seat of Albany's government.
The First Church in Albany (Reformed) is the oldest congregation in Upstate New York.
WTEN (headquarters pictured), WXXA, and Spectrum News broadcast from within city limits.
Albany-Rensselaer Amtrak Station
Albany International Airport
The Port of Albany-Rensselaer adds $428 million to the Capital District's $70.1 billion gross product.
Siena guard Ronald Moore dribbles toward the basket in a game against Loyola in January 2010.

The highest natural point in Albany is a USGS benchmark near the Loudonville Reservoir off Birch Hill Road, at 378 ft above sea level.

Map of Broome County, New York showing towns and villages. For map key, click on image.

Broome County, New York

Broome County in the U.S. state of New York, as of the 2020 United States Census, had a population of 198,683.

Broome County in the U.S. state of New York, as of the 2020 United States Census, had a population of 198,683.

Map of Broome County, New York showing towns and villages. For map key, click on image.

The county's highest point is in the northwest of the county, a U.S. National Geodetic Survey benchmark known as Slawson atop an unnamed hill in the Town of Sanford.

Excavations at the site of Gran Dolina, in the Atapuerca Mountains, Spain, 2008

Archaeological excavation

Exposure, processing and recording of archaeological remains.

Exposure, processing and recording of archaeological remains.

Excavations at the site of Gran Dolina, in the Atapuerca Mountains, Spain, 2008
Excavations at Faras, Sudan, 1960s
Excavations at the cave of Santa Ana (Cáceres, Extremadura, Spain)
Stratigraphy in the excavation area in the Kerameikos Cemetery (Athens).
Stratification at an excavation site in Augsburg, Germany
Horse burial in Roman ditch on a development funded site in London. Note "out of phase" pipe intrusion left in for practical reasons
Excavation in phase has reduced this site to the occupation level of a Romano-Celtic temple (56 Gresham Street, London)
Excavation at the site of the Battle at the Harzhorn (Germany)

Heights are recorded with a dumpy level or total station by relation to the site temporary benchmark (abbr.