围栏转化

	public static double Ea = 6378137;     //   赤道半径  
    public static double Eb = 6356725;     //   极半径 

    public static Point GetJWDB(double GLON,double GLAT,double distance,double angle){
        double dx = distance * Math.sin(angle * Math.PI / 180.0);
        double dy = distance * Math.cos(angle * Math.PI / 180.0);
        //double ec = 6356725 + 21412 * (90.0 - GLAT) / 90.0;
        // 21412 是赤道半径与极半径的差
        double ec = Eb + (Ea-Eb) * (90.0 - GLAT) / 90.0;
        double ed = ec * Math.cos(GLAT * Math.PI / 180);
        double bjd = (dx / ed + GLON * Math.PI / 180.0) * 180.0 / Math.PI;
        double bwd = (dy / ec + GLAT * Math.PI / 180.0) * 180.0 / Math.PI;
        return new Point(bjd, bwd);
    }
	
	
    public static List<Point> getCirclePoints(PGcircle circle){
    	List<Point> points=new ArrayList<>();
    	Point circleCenter=new Point(circle.center.x,circle.center.y);
    	for(int i=0;i<360;i=i+30){
    		Point p = GetJWDB(circleCenter.x,circleCenter.y,circle.radius,i);
    		points.add(p);
    	}
    	points.add(points.get(0));
    	return points;
    }
    ```