php计算距离的代码一例

代码如下：

<?php
/**
* 根据经纬度计算距离
* by http://www.jb200.com
*/
function distance($lat1, $lon1, $lat2, $lon2, $unit) {  
  $theta = $lon1 - $lon2; 
  $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta)); 
  $dist = acos($dist); 
  $dist = rad2deg($dist); 
  $miles = $dist * 60 * 1.1515; 
  $unit = strtoupper($unit); 
 
  if ($unit == "K") { 
    return ($miles * 1.609344); 
  } else if ($unit == "N") { 
      return ($miles * 0.8684); 
    } else { 
        return $miles; 
      } 
}

//调用示例
echo distance(32.9697, -96.80322, 29.46786, -98.53506, "k")." kilometers";
?>