根据两点的经纬度计算直线距离

<?php 
/**
*  @desc 根据两点间的经纬度计算距离
*  @param float $lat 纬度值
*  @param float $lng 经度值
*/
 function getDistance($lat1, $lng1, $lat2, $lng2)
 {
     $earthRadius = 6367000; //approximate radius of earth in meters

     /*
       Convert these degrees to radians
       to work with the formula
     */

     $lat1 = ($lat1 * pi() ) / 180;
     $lng1 = ($lng1 * pi() ) / 180;

     $lat2 = ($lat2 * pi() ) / 180;
     $lng2 = ($lng2 * pi() ) / 180;

     /*
       Using the
       Haversine formula

       http://en.wikipedia.org/wiki/Haversine_formula

       calculate the distance
     */

     $calcLongitude = $lng2 - $lng1;
     $calcLatitude = $lat2 - $lat1;
     $stepOne = pow(sin($calcLatitude / 2), 2) + cos($lat1) * cos($lat2) * pow(sin($calcLongitude / 2), 2);  $stepTwo = 2 * asin(min(1, sqrt($stepOne)));
     $calculatedDistance = $earthRadius * $stepTwo;

     return round($calculatedDistance);
 }

     $lat1='36.8274190000';
     $lng1='118.0484210000';
     $lat2='36.8419400000';
     $lng2='118.0494970000';
    echo  getDistance($lat1, $lng1, $lat2, $lng2);