Measurement of Plane Areas.
III. Measurement of Large Areas.
Adjustment of Drawing and Instrument.
Following our division of the methods of Measurement of Plane Areas we
come to the Second Method or Method of Measuring Large Areas. This method,
stated at the beginning, is the one used when the extent or shape of
the figure whose area is desired is such that every point on its periphery
cannot be reached by the Tracer from one position of the Pole with the
Pole on the outside of the given figure. As indicated by the term
“Measurement with Interior Pole” commonly applied to designate this method,
the Pole of the Planimeter is placed within the given figure to be measured,
usually at or near the center of the figure, and the Tracer makes a complete
revolution about the Pole as a center while tracing the periphery of the
The operation of measuring the area of a plane figure by this method
is quite as simple as that just described and is as