Units of MeasureListed below are the units of measure that surveyor’s use and what they mean. Need help? Give us a call at 757-345-2866. |
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Acre: A unit of area equal to 43,560 square feet, 10 square chains, or 160 square poles. A square mile is 640 acres. Engineer’s Chain: A 100-foot chain containing 100 links each of which is 1-foot long. Furlong: Unit of length equal to 40 poles (220 yards). Its name derives from “furrow long”, the length of a furrow that oxen can plow before they are rested and turned. See Gunter’s chain. Gunter’s chain: Unit of length equal to 66 feet or 4 poles. Developed by English polymath Edmund Gunter in the early 1600s. The standard measuring chain revolutionized surveying. Gunter’s chain was 22 yards long or 1/10 of a furlong, a common unit of length in the old days. An area 1 chain wide by 10 chains long was exactly one acre. In 1595 Queen Elizabeth I had the mile redefined from the old Roman value of 5,000 feet to 5,280 feet in order for it to be an even number of furlongs. A mile is 80 chains. Hectare: Metric unit of area equal to 10,000 square meters or 2.471 acres. League: A unit of length that is approximately 3 miles. |
Link: A unit of length equal to 1/100 chain (7.92 inches). Out: An “out” was 10 chains. When counting out long lines, chain carriers would put a stake at the end of a chain, move the chain and put another stake at the end, and so on until they ran “out” of ten stakes. Perch: See Pole. Point: A point of the compass. There are four cardinal points (north, south, east, west), and 28 others yielding 32 points of 11.25 degrees each. A survey line's direction could be described as a compass point, as in “NNE” (North Northeast). To improve precision, the points would be further subdivided into halves or quarters as needed. Pole: Unit of length and area also known as a perch or rod. As a unit of length, one pole equals 16.5 feet. A mile is 320 poles. As a unit of area, equal to a square with sides one pole long, an acre is 160 square poles. It was common to see an area referred to as "87 acres, 112 poles", meaning 87 and 112/160 acres. Rathbone’s chain: A measuring chain two poles, or 33 feet, in length. Rod: See Pole. Rood: Unit of area usually equal to 1/4 acre. |