Gunter’s chain at Campus Martius Cricket ground measurement with diagram pdf. Gunter developed an actual measuring chain of 100 links.
100 links, usually marked off into groups of 10 by brass rings or tags which simplify intermediate measurement. Each link is thus 7. Gunter’s chain reconciled two seemingly incompatible systems: the traditional English land measurements, based on the number four, and the newly introduced system of decimals based on the number 10. 10 square chains in Gunter’s system, the entire process of land measurement could be computed in decimalised chains and links, and then converted to acres by dividing the results by 10. 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. 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. 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. 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.
This unit still exists as a location identifier on British railways, as well as in some areas of America. In the Midwest of the US it is not uncommon to encounter deeds with references to chains, poles, or rod units, especially in farming country. Minor roads surveyed in Australia and new Zealand were in the 19th and early 20th centuries customarily one chain wide. In some places other lengths have been used, for example 8. 90-inch links, most commonly as 33-foot half-chains of 40 links. These chains were sometimes used in the American colonies, particularly Pennsylvania. Longman, Brown, Green and Longmans.
Chapter 2, Section 8: Public Roads. New Zealand Institute of Surveyors. The Colonial Surveyor in Pennsylvania”, Surveyors Historical Society, 2013. This page was last edited on 9 August 2017, at 23:46.