Leonardo da Vinci's odometer measured distance by counting the rotations of a wheel.
Leonardo designed a mechanical distance-measuring device for surveying and mapmaking. As a wheel rolled along the ground, its motion was transmitted through gears to a box that released a small object at regular intervals. Counting the released objects indicated how far the wheel had traveled.
The device is usually described as a wheel odometer. Its accuracy depended on the wheel's circumference, the gearing, and the ground surface. It did not directly measure speed or altitude, which are the jobs of a speedometer and an altimeter.
Odometers existed in earlier forms, including ancient distance-measuring instruments associated with Greek and Roman engineering. Leonardo's design belongs to the Renaissance tradition of improving practical mechanical instruments for roads, canals, military surveys, and architecture.