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Gunter's chain at Campus Martius Museum.JPG

Gunter's chain (also known as Gunter’s measurement or Surveyor’s measurement) is a geodetic measuring device used for land survey. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter (1581–1626) long before the development of the theodolite and other more sophisticated equipment, enabling plots of land to be accurately surveyed and plotted, for legal and commercial purposes.

Gunter used an actual measuring chain of 100 links. These, the chain and the link, have become units of their own.


1 Gunter's chain =
SI units
20.12 m 2,012 cm
US customary / Imperial units
22.00 yd 66.00 ft
1 Gunter's link =
SI units
0.2012 m 201.2 mm
US customary units (Imperial units)
0.6600 ft 7.920 in

The chain is divided into 100 links, marked off into groups of 10 by brass rings which simplify intermediate measurement. Each link is 7.92 inches long, with 10 links making slightly less than 6 feet 8 inches. The full length of the chain is 66 feet. A square link is exactly one hundred-thousandth of an acre and one ten-thousandth of one square chain or 0.0404685642 m². It is about 62¾ square inches.

Gunter's chain reconciled two seemingly incompatible systems: the traditional English land measurements, based on the number 4, and the newly introduced system of decimals based on the number 10. Since an acre measured 10 square chains in Gunter's system, the entire process of land measurement could be computed in decimalized chains and links, and then converted to acres by dividing the results by 10.[1]


The method of surveying a field or other parcel of land with Gunter's chain is to first determine corners and other significant locations, and then to measure the distance between them, taking two points at a time. The surveyor is assisted by a chainman. A ranging rod (usually a prominently coloured wooden pole) is placed in the ground at the destination point. Starting at the originating point the chain is laid out towards the ranging rod, and the surveyor then directs the chainman to make the chain perfectly straight and pointing directly at the ranging rod. A pin is put in the ground at the forward end of the chain, and the chain is moved forward so that its hind end is at that point, and the chain is extended again towards the destination point. This process is called ranging, or in the US, chaining; it is repeated until the destination rod is reached, when the surveyor notes how many full lengths (chains) have been laid, and he can then directly read how many links (one-hundredth parts of the chain) are in the distance being measured.

The whole process is repeated for all the other pairs of points required, and it is a simple matter to make a scale diagram of the plot of land. The process is surprisingly accurate and requires only very low technology. Surveying with a chain is simple if the land is level and continuous—it is not physically practicable to range across large depressions or significant waterways, for example. The triangulation method requires that the land is plane (not varying significantly in slope). On sloping land, the chain was to be "leveled" by raising one end as needed, so that undulations did not increase the apparent length of the side or the area of the tract.[2]

Unit of length[edit]

Although Gunter's chain was later superseded by the steel tape (a form of tape measure), its legacy was a new unit of length called the chain, which measured 66 feet (or 100 links).[3] This unit still exists as a location identifier on British railways, as well as in some areas of Australia and America. In the United States, for example, Public Lands Survey plats are published in the chain unit to maintain the consistency of a two-hundred-year-old database.

In some places other lengths have been used, for example 8.928 inches (ca. 0.227 m) in Scotland and 10.08 inches (ca. 0.256 m) in Ireland.[citation needed]

The length of a cricket pitch is exactly one chain (22 yards).[4]

Similar measuring chains[edit]

A similar American system, of lesser popularity, is Ramsden’s or the engineer’s system, where the chain consists also of 100 links, each one foot (0.3048 m) long

The even less common Rathborn system, also from the 17th century, is based on a 200-link chain of two rods (33 feet, 10.0584 m) length. Each rod (perch) consists of 100 links, (1.98 inches, 50.292 mm each), which are called seconds (″), ten of which make a prime (′, 19.8 inches, 0.503 m). [5]

Vincent Wing made chains with 9.90 inch links, most commonly as 33-ft half-chains of 40 links. These chains were sometimes used in the American colonies, particularly Pennsylvania. [6]

See also[edit]


  1. ^ Linklater, Andro (2003). Measuring America. Penguin. pp.16–17.
  2. ^ Holloway, Thomas (1881). The practical surveyor. Horace Cox. London. pp.22–24. Retrieved April 7, 2009.
  3. ^ Nesbit, Anthony (1847). A complete treatise on practical land-surveying, Ninth edition. Longman, Brown, Green and Longmans. London. p. 29. Retrieved April 7, 2009.
  4. ^ Craven, Ian; Gray, Martin; Stoneham, Geraldine (1994). Australian Popular Culture. Cambridge University Press. p. 27. ISBN 0-521-46667-9.
  5. ^ Zupko, Ronald Edward. A Dictionary of Weights and Measures for the British Isles
  6. ^ Denny, Milton. "The Colonial Surveyor in Pennsylvania", Surveyors Historical Society, 2013.

External links[edit]

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Gunter's_chain — Please support Wikipedia.
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79 news items

The Hindu

The Hindu
Thu, 15 May 2014 06:52:30 -0700

NC Scriber, which were used to create or change drawings, hand press, binoculars, trough compass, tracing table, dumpy level, optical square, meter chains, its predecessor Gunter's Chain, and English and French pantographs are among the exhibits, along ...
Hometown Focus
Thu, 20 Feb 2014 17:41:32 -0800

Gunter's chain at Campus Martius Museum. Source: Wikipedia.org. As if they did not have enough to deal with in the years following 1776, our founding fathers had to come up with a way of satisfying that hunger described by Frost. That required finding ...

Mille Lacs County Times (blog)

Mille Lacs County Times (blog)
Wed, 12 Mar 2014 09:30:00 -0700

Although astronomic observations were used to establish some survey positions long ago, much of the section corner work was performed with a Gunter's chain and a surveyor's compass, Delles explained. The Gunter's or surveyor's chain was 66 feet long, ...
Aitkin Independent Age
Wed, 26 Feb 2014 04:15:32 -0800

Surveyors used a Gunter's chain and a compass. During his work, Delles uses historical records and does research within the county which is double checked with the work his crew is doing. A map and verified section corners throughout the county can be ...
New York Times
Tue, 03 Dec 2013 16:57:14 -0800

Together, in chronicling the history of the United States Public Land Survey System, the books maintain that the conquest of the American West owed more to the surveyor's line (or “Gunter's chain,” as it is known) than to the Conestoga wagon or the ...
Wired (blog)
Fri, 10 Dec 2010 04:03:17 -0800

He also invented Gunter's chain, a surveying instrument with 100 links. With a length of exactly 22 yards (or 4 rods or 1/10 furlong), it was 1/80 mile. One square chain is 66 feet by 66 feet, or 4,356 square feet, and an acre is conveniently 10 square ...
Wed, 08 May 2013 12:40:00 -0700

1816-1834); and a set of 18th-century Gunter's Chain (survey chain) of the type that Mason and Dixon would have used to measure distance on land. Lastly, the exhibition will display images of Mason-Dixon markers in the 20th century taken by Dr. Allie L.
Cochrane Times
Thu, 08 Dec 2011 13:27:57 -0800

Links of Gunter's Chain are eight inches, of heavy gauge wire and with a loop at each end. These were joined end to end, and enabled the chain to be folded up, link by link, until all 100 were in a bundle which could be held in one hand. At each of the ...

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