地图算法（四）：判断当前点是不是在圆内

public class CircleAreaJudge {
    private double cx = 0.0D;
    private double cy = 0.0D;
    private double r = 0.0D;

    public CircleAreaJudge(double x, double y, double r) {
        try {
            this.cx = x;
            this.cy = y;
            this.r = r;
        } catch (NumberFormatException localNumberFormatException) {
        }
    }

    public boolean isInArea(double x, double y) {
        return isInArea(x, y);
    }


    public boolean isInArea(String x, String y) {
        double dis = RuleUtil.computeLength(Double.parseDouble(x), Double.parseDouble(y), this.cx, this.cy);
        if (dis < this.r) {
            return true;
        }
        return false;
    }

    public static void main(String[] args) {
        CircleAreaJudge circleAreaJudge=new CircleAreaJudge(2.0, 2.0, 1);
        System.out.println(circleAreaJudge.isInArea("1","1"));
    }
}

RuleUtil.computeLength

    public static double computeLength(double dwStartX, double dwStartY, double dwEndX, double dwEndY) {
        double PI = 3.1415926535898D;

        double latRadians1 = dwStartY * (PI / 180.0D);
        double latRadians2 = dwEndY * (PI / 180.0D);
        double latRadians = latRadians1 - latRadians2;
        double lngRadians = dwStartX * (PI / 180.0D) - dwEndX * (PI / 180.0D);
        double f = 2.0D * Math.asin(Math.sqrt(Math.pow(Math.sin(latRadians / 2.0D), 2.0D)
                + Math.cos(latRadians1) * Math.cos(latRadians2) * Math.pow(Math.sin(lngRadians / 2.0D), 2.0D)));
        return f * 6378137.0D;
    }

转载自：https://blog.csdn.net/liu3364575/article/details/78393292