php根据坐标计算距离

//获取2点之间的距离
function GetDistance($lat1, $lng1, $lat2, $lng2){ 
    $radLat1 = $lat1 * (PI / 180);
    $radLat2 = $lat2 * (PI / 180);
   
    $a = $radLat1 - $radLat2; 
    $b = ($lng1 * (PI / 180)) - ($lng2 * (PI / 180)); 
   
    $s = 2 * asin(sqrt(pow(sin($a/2),2) + cos($radLat1)*cos($radLat2)*pow(sin($b/2),2))); 
    $s = $s * EARTH_RADIUS; 
    $s = round($s * 10000) / 10000; 
    return $s; 

}