关于角度量分类的探讨

常用的“角度”是指国际单位制中的“平面角”，因此分类的出发点应是 “平面角”的平面特性，平面分为几何面与物理面，因此，角度可分为几何角与物理角两类。几何角分为：任意角（圆分度角），定角，小角；物理角分为：水平面投影角，铅垂面投影角，特定面投影角。这种新的分类方法作为一项建议提供讨论。

Discussions on the Classification of Angle Quantity

The frequently used angle was the plane angle in the International System of Units, so the starting point of classification should be the plane performance of the plane angle. Because of the plane was divided into geometric plane and physical plane, so the plane angle could be divided into two parts: geometric angle and physical angle. The geometric angle was divided into arbitrary angle (circle indexing angle), fixed angle and small angle; the physical angle was divided into projection angle on horizontal plane, projection angle on vertical plane and projection angle on specific plane. The new classification method was proposed just as suggestion for discussions.