iOS 地图 通过经纬度计算两点间距离

- (double)calculateStart:(CLLocationCoordinate2D)start end:(CLLocationCoordinate2D)end {

    double meter = ;

    double startLongitude = start.longitude;
    double startLatitude = start.latitude;
    double endLongitude = end.longitude;
    double endLatitude = end.latitude;

    double radLatitude1 = startLatitude * M_PI / 180.0;
    double radLatitude2 = endLatitude * M_PI / 180.0;
    double a = fabs(radLatitude1 - radLatitude2);
    double b = fabs(startLongitude * M_PI / 180.0 - endLongitude * M_PI / 180.0);

    double s =  * asin(sqrt(pow(sin(a/),) + cos(radLatitude1) * cos(radLatitude2) * pow(sin(b/),)));
    s = s * EARTH_RADIUS;

    meter = round(s * ) / ; //返回距离单位是米
    return meter;
}

//赤道半径

EARTH_RADIUS = 6378137;

//start 起点经纬度,数据格式 start = {lon:,lat:}

//end 终点定位度,数据格式 end = {lon:,lat:}