<< Previous Section Table of Contents The Polar Planimeter Page Numbers Next Section >>

CHAPTER IV.

Measurement of Plane Areas.

III. Measurement of Large Areas.

Accuracy of Results.

Of the relative accuracy in results obtained by the two methods just described there seems to be a diversity of opinion. Some authorities claim that while the second method of measurementó with Pole in the interior of the figureó may and does give results with a degree of accuracy well within allowable error in most instances, the measurement by the first or exterior pole method is much more accurate and free from probability and chance of error, and hence when required to measure an area whose size wound preclude measurement of the whole by the exterior pole method, always divide the given large area by diagonal straight lines into constituent small areas, and measuring each independently by the first method, add, the results for the total area.

Others again claim to get equally accurate results by either form of measurement and the experience of the writer has been that there are very few instances in which with careful operating, results obtained by the second method are not of a degree of accuracy well within the permissible limit of error and entitled to confidence in their use.

It is however advisable to always use the first method when the size of the figure will permit and when the size of the given figure does not allow of the first to use the second method, checking in cases requiring great accuracy by subdividing and independently measuring the areas of the subdivisions.

<< Previous Section Table of Contents The Polar Planimeter Page Numbers Next Section >>