Question

what is an opisometer and how does it work

Answer 1

HERE'S YOUR ANSWER!!

opisometer is an instrument used for measuring curved lines(as on a map) and consisting essentially of a screw with a wheel shaped nut that is made to rotate forward along the curved lines and then backward to its original position on the screw along a straight scale.
A simple opisometer consist of toothed wheel of known circumference on a handle. The wheel is placed in contact with curved line to be measured and run along its length. The instrument is commonly used to measure the lengths of road,rivers and other line features on maps.

hope this helps u:-)

Answer 2

A simple opisometer consists of a toothed wheel of known circumference on a handle. The wheel is placed in contact with the curved line to be measured and run along its length. ... The instrument is most commonly used to measure the lengths of roads, rivers and other line features on maps.