直角坐标系用三角函数判断旋转方向和旋转角度

坐标原点知道

两个点知道

相对于坐标原点的旋转的角度可以通过三角函数算出来

因为知道了三个边的长度，

Math.acos((bb*bb+cc*cc-aa*aa)/(2*bb*cc))

主要就是这个方法

至于旋转x1*y2-x2*y1大于0就是顺时针，小于0就是逆时针，考虑原点的位置

public class DirectionClass {

    public double x0=LambdaTest01.InterSectionLat;
    public double y0=LambdaTest01.InterSectionLng;
    
    //给定两个点的方向，判断怎么转向的
    //首先确定大方向就是用路口的定点作为基准点，两个点作为偏置点，制作到一个三角形然后用三个边判断两个点的角度。关键是如何判断顺时针还是逆时针。
    public static double directionTurned(double x1,double y1,double x2,double y2) {
        double result=0;
        double bb=lengthConvert.getDistance(x1, y1, LambdaTest01.InterSectionLat, LambdaTest01.InterSectionLng);
        double cc=lengthConvert.getDistance(x2, y2, LambdaTest01.InterSectionLat, LambdaTest01.InterSectionLng);
        double aa=lengthConvert.getDistance(x1, y1, x2, y2);
        result=Math.acos((bb*bb+cc*cc-aa*aa)/(2*bb*cc));
        double fix=180/Math.PI;
        return result*fix;
    }
    public static double directionTurned_bd(double x1,double y1,double x2,double y2) {
        double result=0;
        double bb=lengthConvert.getDistance(x1, y1, LambdaTest01.testInterSectionLat, LambdaTest01.testInterSectionLng);
        double cc=lengthConvert.getDistance(x2, y2, LambdaTest01.testInterSectionLat, LambdaTest01.testInterSectionLng);
        double aa=lengthConvert.getDistance(x1, y1, x2, y2);
        result=Math.acos((bb*bb+cc*cc-aa*aa)/(2*bb*cc));
        double fix=180/Math.PI;
        return result*fix;
    }
    public static double directionTurned2(double x1,double y1,double x2,double y2) {
        double result=0;
        double bb=lengthConvert.getDistance2(x1, y1, 0, 0);
        double cc=lengthConvert.getDistance2(x2, y2, 0, 0);
        double aa=lengthConvert.getDistance2(x1, y1, x2, y2);
        System.out.println(bb);
        System.out.println(cc);
        System.out.println(aa);
        double fix=180/Math.PI;
        result=Math.acos((bb*bb+cc*cc-aa*aa)/(2*bb*cc));
        return result*fix;
    }
    public static boolean wise_anti(double x1,double y1,double x2,double y2) {
        double result=(x1-LambdaTest01.InterSectionLat)*(y2-LambdaTest01.InterSectionLng)-(x2-LambdaTest01.InterSectionLat)*(y1-LambdaTest01.InterSectionLng);
        if (result>=0) {
            System.out.println("顺时针");
            return true;
        }else {
            System.out.println("逆时针");
            return false;    
        }
    }
    public static boolean wise_anti_bd(double x1,double y1,double x2,double y2) {
        double result=(x1-LambdaTest01.testInterSectionLat)*(y2-LambdaTest01.testInterSectionLng)-(x2-LambdaTest01.testInterSectionLat)*(y1-LambdaTest01.testInterSectionLng);
        if (result>=0) {
            System.out.println("顺时针");
            return true;
        }else {
            System.out.println("逆时针");
            return false;    
        }
    }
    
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        double result=directionTurned2(1, 0, 0, 1);
        System.out.println(result);
    }

}