Reference Page:

Convert Degrees Minutes Seconds to Decimal Degrees and vice-versa 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.

---------------------------------------------------------------

 One Inches Feet Yards Statute Miles Nautical Miles mm Inch 1 0.0833 0.0277 25.4 Foot 12 1 0.333 304.8 Yard 36 3 1 0.00056 914.4 Statute Mile 63,360 5,280 1,760 1 0.8684 Nautical Mile 72,963 6,080 2,026 1.1516 1 Millimeter 0.0394 0.0033 0.0011 1 Centimeter 0.3937 0.0328 0.0109 10 Decimeter 3.937 0.328 0.1093 100 Meter 39.37 3.2808 1.0936 0.0006 0.0005 1,000 Decameter 393.7 32.81 10.94 0.0062 0.0054 10,000 Hactometer 3,937 328.1 109.4 0.0621 0.0539 100,000 Kilometer 39,370 3,281 1,094 0.6214 0.5396 1,000,000 Myriameter 393,700 32,808 10,936 6.2137 5.3959 10,000,000

Metric System of Linear Measure

 1 millimeter = 0.1 centimeter = 0.0393 inch 10 millimeter = 1 centimeter = 0.3937 inch 10 centimeters = 1 decimeter = 3.937 inches 10 decimeters = 1 meter = 39.37 inches 10 meters = 1 decameter = 32.81 feet 10 decameters = 1 hectometer = 328.1 feet 10 hectameters = 1 kilometer = 0.62 mile 10 kilometers = 1 myriameter = 6.21 miles

Linear Measure / Long Measure

 1 Mile = 80 Chains = 320 Rods = 5,280 Feet 1 Chain = 4 Rods 66 Feet 100 Links 1 Rod = 5 1/2 Yards 16 1/2 Feet 25 Links 1 Link = 0.66 Feet 7 7/8 Inches 1 Pole = 16 1/2 Feet

Square Measure

 1 Sq Mile = 640 Acres 1 Acre = 10 Sq Chains 160 Sq Rods 43,560 Sq Feet 1 Sq Rod = 30 1/4 Sq Yards 272 1/4 Sq Feet 1 Sq Foot = 144 Sq Inches 1 Furlong = 220 Yards = 1/8 Mile

Surveying Units of 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.

Return to Top of Page