Question

所以我正在尝试构建一个程序来帮助我模拟/调整我的无人机飞行，起点是计算坐标之间的精确距离。所以我正在使用一些我发现的PHP，但我不能“开始”。输入坐标后，该函数无法返回距离$ d。我认为这可能是基于先前答案的范围问题，但我迷路了。您的见解将不胜感激。谢谢！

<?php

    global $lat1;
    global $lon1;
    global $lat2;
    global $lon2;

    function vincenty($lat1, $lon1, $lat2, $lon2) {
    // Equatorial Radius
    $a = 6378137.0;
    // Polar Radius
    $b = 6356752.31424518;
    // Flattening of the ellipsoid
    $f = 0.00335281066;
    // Difference in longitude
    $L = $lon2 - $lon1;
    $U1 = atan((1 - $f) * tan($lat1));  //U is 'reduced latitude'
    $U2 = atan((1 - $f) * tan($lat2));
    $sinU1 = sin($U1);
    $sinU2 = sin($U2);
    $cosU1 = cos($U1);
    $cosU2 = cos($U2);

    $lambda = $L;
    $lambdaP = 2 * pi();
    $i = 20;

    while (abs($lambda - $lambdaP) > 1e-12 && --$i > 0) {
            $sinLambda = sin($lambda);
            $cosLambda = cos($lambda);
            $sinSigma = sqrt(($cosU2 * $sinLambda) * ($cosU2 * $sinLambda) + ($cosU1 * $sinU2 - $sinU1 * $cosU2 * $cosLambda) * ($cosU1 * $sinU2 - $sinU1 * $cosU2 * $cosLambda));

            if ($sinSigma == 0)
                    return 0;  // coincident points

            $cosSigma = $sinU1 * $sinU2 + $cosU1 * $cosU2 * $cosLambda;
            $sigma = atan2($sinSigma, $cosSigma);
            $sinAlpha = $cosU1 * $cosU2 * $sinLambda / $sinSigma;
            $cosSqAlpha = 1 - $sinAlpha * $sinAlpha;
            $cos2SigmaM = $cosSigma - 2 * $sinU1 * $sinU2 / $cosSqAlpha;
            if (is_nan($cos2SigmaM))
                    $cos2SigmaM = 0;  //equatorial line: cosSqAlpha=0 (6)
            $c = $f / 16 * $cosSqAlpha * (4 + $f * (4 - 3 * $cosSqAlpha));
            $lambdaP = $lambda;
            $lambda = $L + (1 - $c) * $f * $sinAlpha * ($sigma + $c * $sinSigma * ($cos2SigmaM + $c * $cosSigma * (-1 + 2 * $cos2SigmaM * $cos2SigmaM)));
    }

    if ($i == 0)
            return false;  // formula failed to converge

    $uSq = $cosSqAlpha * ($a * $a - $b * $b) / ($b * $b);
    $A = 1 + $uSq / 16384 * (4096 + $uSq * (-768 + $uSq * (320 - 175 * $uSq)));
    $B = $uSq / 1024 * (256 + $uSq * (-128 + $uSq * (74 - 47 * $uSq)));
    $deltaSigma = $B * $sinSigma * ($cos2SigmaM + $B / 4 * ($cosSigma * (-1 + 2 * $cos2SigmaM * $cos2SigmaM) - $B / 6 * $cos2SigmaM * (-3 + 4 * $sinSigma * $sinSigma) * (-3 + 4 * $cos2SigmaM * $cos2SigmaM)));
    $d = $b * $A * ($sigma - $deltaSigma);
    return $d;
}

    class ConsoleQuestion
    {

        function readline()
        {
            return rtrim(fgets(STDIN));
        }
    }

    $line = new ConsoleQuestion();
    $prompt = "Enter starting latitude: ";
    echo $prompt;
    $lat1 = deg2rad($line->readline());

    $line = new ConsoleQuestion();
    $prompt = "Enter starting longitude: ";
    echo $prompt;
    $lon1 = deg2rad($line->readline());

    $line = new ConsoleQuestion();
    $prompt = "Enter ending latitude: ";
    echo $prompt;
    $lat2 = deg2rad($line->readline());

    $line = new ConsoleQuestion();
    $prompt = "Enter ending longitude: ";
    echo $prompt;
    $lon2 = deg2rad($line->readline());

    vincenty($lat1,$lon1,$lat2,$lon2);

    echo("Total distance is: $d\n");

?>

php - 未调用用户定义的函数

0 个答案: