A curvimeter (from the Latin curvus - curved) is a device with which the length of winding lines on plans, drawings and maps is measured.
The curvimeter is simple in design and consists of a toothed roller of a known diameter on the handle and a counter of the passed number of teeth. To measure the length of the curve, roll it with a curvimeter roller. Such curvimeters are called mechanical and have been used to measure distances for more than a millennium. Recently, electronic curvimeters have begun to be produced, equipped with an LCD display on which the measurement results are displayed. But this does not change the essence, except that the measurement error decreases.