The curvimeter (aka map meter or opisometer) is an instrument used to measure curved lines. It can calculate the distance between points on a map more accurately than a ruler or compass. The mechanism has a measuring wheel, a clock dial and an arrow. When you run the curvimeter along the curved line you measure; the arrow moves around the clock dial, which is marked in units of measurement (centimeters, inches, etc.). All you have to do is check the scale of the map and multiply your data by the scale denominator. The curvimeter is a handy tool for cartographers, tourists and road services that you can use when hiking and family trips to remote areas without internet access to accurately determine the distance to your destination.