简易量积仪，虽然式样极为简章，但用以量算各种形状的平面面积，其效能实深为优良，且不亚于常用的量积仪。此种量积仪亦可称谓“双曲线三角”。其原理及其实用方法详述如下。 Simple product plotter, although the style is very simple, but to measure the various shapes of the planar area, its performance is really good deep, and no less than the commonly used totalizer. This plotter can also be called “hyperbolic triangle.” The principle and practical methods are described in detail below.