Sorensen's Wheel

Sorensen's Wheel, also known as a polar planimeter, is a precision instrument used to measure the area of irregular shapes on a plane, such as geographical maps or land plots. It consists of a tracer arm attached to a wheel that moves along the perimeter of the shape. As the wheel rolls, it records the boundary's length precisely. The device then calculates the enclosed area based on this movement, providing an accurate measurement without needing to divide the shape into smaller sections. It’s a useful tool in surveying, cartography, and engineering for efficient area measurement.