使用纬度-经度计算两个地方之间的距离，在java中得到错误的距离

Question

i am using haversine formula to calculate distance but i am getting wrong distance actually google map distance is 8.1km but haversine formula is showing 4.06

private static final int EARTH_RADIUS = 6371; // Approx Earth radius in KM

public static double distance(double startLat, double startLong, double endLat, double endLong) {

    double dLat = Math.toRadians((endLat - startLat));
    double dLong = Math.toRadians((endLong - startLong));

    startLat = Math.toRadians(startLat);
    endLat = Math.toRadians(endLat);

    double a = haversin(dLat) + Math.cos(startLat) * Math.cos(endLat) * haversin(dLong);
    double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

    return EARTH_RADIUS * c; // <-- d
}

public static double haversin(double val) {
    return Math.pow(Math.sin(val / 2), 2);
}

Answer 1

Your formula is correct, the problem come from bad use of google map

As suggested by Tim in comments, you need to see the point-to-point distance, not road distance

Using the two distance(17.451955, 78.478187, 17.442504, 78.441323) give 4.06km:

8.1km is probably the distance by road, and not point-to-point