我们在测量公路弯道的时候,常常应用切线支距法来控制弯道的中间各点,比较间捷便利。当x轴控制长度为R的某倍时,则y控制的长度与R的关系,也是相应的倍数。如图1 设x=nR R~2=x~2+yo~2=(nR)~2+yo~2 通过计算,可以显示出在各种不同半经的曲线上,采用相同的x与R的比值,和求得的y与R的比值,在坐标关系上是一根直线(如图2)。 When we measure the curve of the road, we often use the method of tangent offset to control the middle of the curve, which is more convenient. When the x-axis control length is a certain length of R, then the relationship between the length of y-control and R is also a corresponding multiple. As shown in Fig. 1, x = nR R ~ 2 = x ~ 2 + yo ~ 2 = (nR) ~ 2 + yo ~ 2 It can be shown that the same x and R Ratio, and the ratio of y and R obtained in the coordinate relationship is a straight line (Figure 2).