PHP实现根据经纬度查找附近的人

$uid=$_POST[uid];
    if($uid>0)
    {
        $re=mysql_query("select `lat`,`long` from pre_common_member where uid='$uid'")or die(mysql_error());
        $row=mysql_fetch_assoc($re);
        if(!empty($row[lat]) and !empty($row[long]))
        {
            $re0=mysql_query("select `username`,`lat`,`long` from pre_common_member where uid!='$uid'");
            while($row0=mysql_fetch_assoc($re0))
            {
                $distance = getDistanceBetweenPointsNew($row['lat'], $row['long'], $row0['lat'], $row0['long']);
                $row0[meter]=$distance[meters];
                $arr[]=$row0;
            }
            $arr=array_sort($arr,'meter');
            $arr = array_slice($arr,0,10); 
            $data=json_encode($arr);
            $s=mysql_errno();
            //echo $data;
            echo "{\\"s\\":$s,\\"data\\":$data}";
        }   
    }

function getDistanceBetweenPointsNew($latitude1, $longitude1, $latitude2, $longitude2)
{
    $theta = $longitude1 - $longitude2;
    $miles = (sin(deg2rad($latitude1)) * sin(deg2rad($latitude2))) + (cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) * cos(deg2rad($theta)));
    $miles = acos($miles);
    $miles = rad2deg($miles);
    $miles = $miles * 60 * 1.1515;
    $feet = $miles * 5280;
    $yards = $feet / 3;
    $kilometers = $miles * 1.609344;
    $meters = $kilometers * 1000;
    return compact('miles', 'feet', 'yards', 'kilometers', 'meters');
}

function array_sort($arr,$keys,$type='asc')
{ 
    $keysvalue = $new_array = array();
    foreach ($arr as $k=>$v){
    $keysvalue[$k] = $v[$keys];
    }
    if($type == 'asc'){
    asort($keysvalue);
    }else{
    arsort($keysvalue);
    }
    reset($keysvalue);
    foreach ($keysvalue as $k=>$v){
    $new_array[$k] = $arr[$k];
    }
    return $new_array; 
}