应用样条表达式计算卵型曲线和反曲线

应用样条表达式进行曲线和反曲线的设计和计算，不但统一了各线元的数学表达式，且由于在各表达式中引入了方位角，使计算方法简便，确定参数的同时进行参数合理性的检验，避免参数选择的错误，可大大提高程序运行的效率，利用积分计算缓和曲线（螺旋线）上各点的坐标，计算结果比近似计算精确.此外，根据样条表达式衔接点处的位置关系，可核实同时位于不同线无上衔接点处参数计算的准确性，利用程序调试。

The Arithmetic of Calculating Oval and Inverse Curve Based on Expression of Spline

Oval and inverse curve are two alignments that are used widely recently in the design of horizontal alignment of highway. The arithmetic of calculating these two kinds of alignment is of diversity because of the complicated connection among their curve elements. Calculating these two kinds of alignment based on expression of spline, not only unifies the mathematical expression of every curve element, but also simplifies the method of calculating.Examining the reasonability of parameters after they are chosen can avoid bringing unreasonable one into the process of calculating and can increase the efficiency of program.Calculating coordinates of the points of easement curve (spiral curve) based on integral can increase the accuracy of the calculating result. In addition, the method is beneficial to debug program by checking connection relationship of the connected points that are located in different curve element at the same time.