Convert Degrees Minutes Seconds to Decimal Degrees and viceversa web page Units of Measure & Conversion Factors Metric System of Linear Measure Square Measure Linear Measure / Long Measure Surveying Units of Measure Notes: The Earth curves approximately 8 inches per mile.  Units of Measure And Conversion Factors
Metric System of Linear Measure
Acre  The (English) acre is a unit of area equal to 43,560 square feet, or 10 square chains, or 160 square poles. It derives from a plowing area that is 4 poles wide and a furlong (40 poles) long. A square mile is 640 acres. The Scottish acre is 1.27 English acres. The Irish acre is 1.6 English acres. Arpent  Unit of length and area used in France, Louisiana, and Canada. As a unit of length, approximately 191.8 feet (180 old French 'pied', or foot). The (square) arpent is a unit of area, approximately .845 acres, or 36,802 square feet. Chain  Unit of length usually understood to be Gunter's chain, but possibly variant by locale. See also Rathbone's chain. The name comes from the heavy metal chain of 100 links that was used by surveyors to measure property bounds. Colpa  Old Irish measure of land equal to that which can support a horse or cow for a year. Approximately an Irish acre of good land. Compass  One toise. Engineer's Chain  A 100 foot chain containing 100 links of one foot apiece. 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. Ground  A unit of area equal to 2400 sq. ft., or 220 sq. meters, used in India. Gunter's Chain  Unit of length equal to 66 feet, or 4 poles. Developed by English polymath Edmund Gunter early in the 1600's, the standard measuring chain revolutionized surveying. Gunter's chain was 22 yards long, one tenth of a furlong, a common unit of length in the old days. An area one chain wide by ten chains long was exactly an acre. In 1595 Queen Elizabeth I had the mile redefined from the old Roman value of 5000 feet to 5280 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, or 107,639 square feet. Hide  A very old English unit of area, a hide was of variable size depending on locale and the quality of the land. It was the amount of land to support a family, and ranged from 60 to 180 acres. After the Norman conquest in 1066 it became standardized at around 120 acres. Hundred  An adminstrative area larger than a village and smaller than a county. In England it was 100 hides in size, and the term was used for early settlements in Virginia, Maryland, and Delaware. Labor  The labor is a unit of area used in Mexico and Texas. In Texas it equals 177.14 acres (or 1 million square varas). League (legua)  Unit of area used in the southwest U.S., equal to 25 labors, or 4428 acres (Texas), or 4439 acres (California). Also, a unit of length approximately three miles. Link  Unit of length equal to 1/100 chain (7.92 inches). Morgen  Unit of area equal to about .6309 acres. It was used in Germany, Holland and South Africa, and was derived from the German word Morgen ("morning"). It represented the amount of land that could be plowed in a morning. Out  An 'out' was ten chains. When counting out long lines, the chain carriers would put a stake at the end of a chain, move the chain and put a 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 necessary, for example, "NE by North, one quarter point North". In some areas, "and by" meant one half point, as in "NE and by North". Pole  Unit of length and area. Also known as a perch or rod. As a unit of length, equal to 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. Pueblo  A Spanish grant of less than 1000 acres. Rancho  A Spanish grant of more than 1000 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. Toise  Traditional French unit of length equal to 6 old French 'pieds' or feet, or 6.4 English feet. Vara  Unit of length (the "Spanish yard") used in the U.S. southwest. The vara is used throughout the Spanish speaking world and has values around 33 inches, depending on locale. The legal value in Texas was set to 33 1/3 inches early in the 1900's. Virgate  An old English unit of area, equal to one quarter of a hide. The amount of land needed to support a person.
