PHP 计算一个用户与其他用户的距离(一一计算)

Question

我试过这段代码，但结果有问题:我只得到 1 公里的结果，其他结果为 0，它进入解决方案或所有用户或没有人。也许我对 mysql_fetch_array 的理解有误。这是 PHP 代码:

<?php
$response = array();
$username=$_POST["user"];
if($username!=null){
$latm=0;
$lonm=0;
mysql_connect("localhost:3306","blabla","lol");
mysql_select_db("my_app");
$posut1=mysql_query(" SELECT lat,lon FROM utenti WHERE user='$username' ");
$posut2= mysql_query(" SELECT lat,lon,user FROM utenti WHERE user!='$username' ");
if($posut1){
$row = mysql_fetch_array($posut1);
list($latm,$lonm)=$row;}
if ($posut2) {
$solutions = array();
$i=0;
while ($row = mysql_fetch_array($posut2))
  {
    list($lat2, $lng2, $us) = $row;
    $lat1=$latm;
    $lng1=$lonm;
    $pi80 = M_PI / 180;
$lat1 *= $pi80;
$lng1 *= $pi80;
$lat2 *= $pi80;
$lng2 *= $pi80;

$r = 6372.797; // mean radius of Earth in km
$dlat = $lat2 - $lat1;
$dlng = $lng2 - $lng1;
$a = sin($dlat / 2) * sin($dlat / 2) + cos($lat1) * cos($lat2) * sin($dlng / 2) * sin($dlng / 2);
$c = 2 * atan2(sqrt($a), sqrt(1 - $a));
$km = $r * $c;
   $kmm[$i]=$km;

      if(km<1000) $solutions[]=$row;
$i++;}  
$response["km"] = $kmm; 
$response["success"] = $solutions;


    // echoing JSON response
    print(json_encode($response));   

} else {
$response["success"] = 0;
    $response["message"] = "dati errati";

    // echoing JSON response
    print(json_encode($response));
}
}
?>

Answer 1

$kmm=array();// add this before while

给你一些信息

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;
      }
}

echo distance(32.9697, -96.80322, 29.46786, -98.53506, "M") . " Miles<br>";
echo distance(32.9697, -96.80322, 29.46786, -98.53506, "K") . " Kilometers<br>";
echo distance(32.9697, -96.80322, 29.46786, -98.53506, "N") . " Nautical Miles<br>";

http://www.geodatasource.com/developers/php