经纬度计算距离算法

经纬度计算坐标

根据经纬度计算两点之间距离算法，经过百度地图标记测试验证比较准确！百度地图标记经纬度网址：http://api.map.baidu.com/lbsapi/getpoint/index.html

算法一：

 

function getDistance($lat1, $lng1, $lat2, $lng2){

    $radLat1=deg2rad($lat1);

    $radLat2=deg2rad($lat2);

    $radLng1=deg2rad($lng1);

    $radLng2=deg2rad($lng2);

    $a=$radLat1-$radLat2;

    $b=$radLng1-$radLng2;

    $s=2*asin(sqrt(pow(sin($a/2),2)+cos($radLat1)*cos($radLat2)*pow(sin($b/2),2)))*6378.137;

    return $s;
}

算法二：

function distance($lat1, $lon1, $lat2,$lon2,$radius = 6378.137)
{
    $rad = floatval(M_PI / 180.0);

    $lat1 = floatval($lat1) * $rad;
    $lon1 = floatval($lon1) * $rad;
    $lat2 = floatval($lat2) * $rad;
    $lon2 = floatval($lon2) * $rad;

    $theta = $lon2 - $lon1;

    $dist = acos(sin($lat1) * sin($lat2) +
        cos($lat1) * cos($lat2) * cos($theta)
    );

    if ($dist < 0 ) {
        $dist += M_PI;
    }

    return $dist = $dist * $radius;
}