measured using the formula A= C*N. For large areas, individual polygons should be solved separately (Knill, 2000).
Kunkle (2001) describes the basic fundamentals behind this mathematical operation. In Figure 3.3, the blue arm (AB) is the anchor arm. It is anchored to the table at Point A, located outside the object to be measured. Point B is the location of the measuring wheel (drum, disk and vernier). The green arm (BC) is the tracing arm, and C is the tracing point. The movement of the anchor arm is restricted to a circle. As the tracing arm moves in a clockwise direction from C to C1, the area dw is measured.
Figure 3.3: Tracing Arm Movement (Kunkle, 2001)
In Figure 3.4, point E divides the area dw into a trapezoid and a triangle to separate the components of the sliding and turning motion of the measurement wheel. Area BCE represents the area covered while the tracing arm is pivoting. During this pivoting motion dθ is the rotation of the arm. Area EC’B’B is the area covered as the tracing arm slides, and dm is the change in the scale reading while