Definition

A mechanical instrument containing a di­stance-measuring element which is moved or turned by an amount proportional to the actual distance travel­led; a compass element which provides a fixed-refe­rence direction, and an integrator which provides for the resolu­tion of the direction of motion into compo­nents and for the summation or integra­tion of the distance com­po­nents. Also an instrument for recording the distance travel­led by a vehicle or pedestrian.