The legal definitions of the English units of measurements are based on metric units. All countries have adopted the metric system, but in the United States the transition is voluntary and not required. There still is a mixture of units for different activities, such as measuring the length of a race in meters and the long jump event in feet.
Meters
The metric unit system bases units on multiples of 10; a meter is a metric unit of length. In 1790, a meter was devised to be one ten-millionth of a quadrant, the distance between the equator and the North Pole. The length is short of that distance by .02 percent. In 1983, the 17th General Conference on Weights and Measures redefined the length of a meter in relation to the speed of light in a vacuum, which is a constant in nature.
Feet
A foot is a unit in the traditional measuring system, which bases measurements on the human body. An inch is the width of a thumb and a foot the length of a human foot. The U.S. National Bureau of Standards defined the measurement of a foot in 1959 as equal to exactly 30.48 cm. Britain also adopted the measurement; that length is now recognized as the international foot.
Meters and Miles
The meter is equal to approximately 1 yard 3 inches, or 39 inches. Based on the length of the international foot, an international statute mile is exactly 1,609.344 m. The United States uses the unit of measurement for the foot from before 1959, called a survey foot, making the U.S. statute mile 1,609.3472 m, or a survey mile. In athletic events, races 1,500 or 1,600 m in length often are referred to as metric miles.
Conversion
Feet can be converted to meters using two values. One conversion is used for geodetic data, based on the survey foot measurement that was used before 1959. Geodetic surveys locate positions, such as latitude, longitude, elevations and shorelines. That type of data calculates the conversion as 1 foot = 12/39.37 m. The conversion used for everything else is 1 foot = 0.3048 m.
References
- University of North Carolina; How Many? A Dictionary of Units of Measurement; Introduction;Russ Rowlett; 2000
- University of North Carolina; How Many? A Dictionary of Units of Measurement; F; Russ Rowlett; 2000
- University of North Carolina; How Many? A Dictionary of Units of Measurement; M; Russ Rowlett; 2000
- Washington State Department of Transportation; The "Foot-to-Meter" Conversion
