Convert from click [U.S. military] to chain [Gunter, survey]

Unit Definition (click [U.S. military])
A click is U.S. military slang for the kilometer (about 0.621 mile). Also spelled klick or klik. This unit became popular during the Vietnam War, but it was invented by U.S. troops in Germany during the 1950s. Occasionally it was used as a non-metric unit equal to 1000 yards (0.9144 kilometer).

Unit Definition (chain [Gunter, survey])
The chain is a unit of distance formerly used by surveyors. The traditional British surveyor's chain, also called Gunter's chain because it was introduced by the English mathematician Edmund Gunter (1581-1626) in 1620, is 4 rods long: that's equal to exactly 1/80 mile, 1/10 furlong, 22 yards, or 66 feet (20.1168 meters). The traditional length of a cricket pitch is 1 chain. Gunter's chain has the useful property that an acre is exactly 10 square chains. The chain was divided into 100 links. American surveyors sometimes used a longer chain of 100 feet, known as the engineer's chain or Ramsden's chain. (However, Gunter's chain is also used in the U.S.; in fact, it is an important unit in the Public Lands Survey System.) In Texas, the vara chain of 2 varas (55.556 ft) was used in surveying Spanish land grants. In the metric world, surveyors often use a chain of 20 meters (65.617 ft).