测绘相关源码 包括：角度化弧度、弧度化角度、计算两点间的方位角、B_三次样条函数（曲线拟合）、贝赛尔曲线。-Surveying and Mapping-related source, including: the angle of curvature, arc angle of the calculation of the azimuth between two points, B_ cubic spline function (curve fitting), Bezier curves.