直角坐標系用三角函數判斷旋轉方向和旋轉角度

坐標原點知道

兩個點知道

相對於坐標原點的旋轉的角度可以通過三角函數算出來

因為知道了三個邊的長度，

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

主要就是這個方法

至於旋轉x1*y2-x2*y1大於0就是順時針，小於0就是逆時針，考慮原點的位置

public class DirectionClass {

    public double x0=LambdaTest01.InterSectionLat;
    public double y0=LambdaTest01.InterSectionLng;
    
    //給定兩個點的方向，判斷怎么轉向的
    //首先確定大方向就是用路口的定點作為基准點，兩個點作為偏置點，制作到一個三角形然后用三個邊判斷兩個點的角度。關鍵是如何判斷順時針還是逆時針。
    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("順時針");
            return true;
        }else {
            System.out.println("逆時針");
            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("順時針");
            return true;
        }else {
            System.out.println("逆時針");
            return false;    
        }
    }
    
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub

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

}