<?php
define('earth_radius', 6378.137);//地球半径
define('pi', 3.1415926);
/**
* 计算两组经纬度坐标 之间的距离
* params :lat1 纬度1; lng1 经度1; lat2 纬度2; lng2 经度2; len_type (1:m or 2:km);
* return m or km
*/
function getdistance($lat1, $lng1, $lat2, $lng2, $len_type = 1, $decimal = 2)
{
$radlat1 = $lat1 * pi / 180.0;
$radlat2 = $lat2 * pi / 180.0;
$a = $radlat1 - $radlat2;
$b = ($lng1 * pi / 180.0) - ($lng2 * pi / 180.0);
$s = 2 * asin(sqrt(pow(sin($a/2),2) + cos($radlat1) * cos($radlat2) * pow(sin($b/2),2)));
$s = $s * earth_radius;
$s = round($s * 1000);
if ($len_type > 1)
{
$s /= 1000;
}
return round($s, $decimal);
}
echo getdistance(39.908156,116.4767, 39.908452,116.450479, 1);//输出距离/米