Question

我在php中有一个坐标数组，如下所示：

Array ( 
    [0] => Array ( 
        [0] => 39.1057579 
        [1] => 26.5451331 
    ) 
    [1] => Array ( 
        [0] => 39.1057579 
        [1] => 26.5451331 
        [2] => 39.1055889 
        [3] => 26.5452403 
    ) 
    [2] => Array ( 
        [0] => 39.1057579 
        [1] => 26.5451331 
        [2] => 39.1055889
    )
)

我将找到一个以start latlng和end latlng作为输入的函数，并返回一个坐标数组作为最短路径。

Answer 1

正如Mark Baker指出的那样，你需要使用类似Dijkstra算法的东西来遍历加权图（这是你在包含距离时所拥有的）。

这是我找到的一个简单的距离函数here：

<?php

/*::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::*/
/*::                                                                         :*/
/*::  This routine calculates the distance between two points (given the     :*/
/*::  latitude/longitude of those points). It is being used to calculate     :*/
/*::  the distance between two locations using GeoDataSource(TM) Products    :*/
/*::                                                                         :*/
/*::  Definitions:                                                           :*/
/*::    South latitudes are negative, east longitudes are positive           :*/
/*::                                                                         :*/
/*::  Passed to function:                                                    :*/
/*::    lat1, lon1 = Latitude and Longitude of point 1 (in decimal degrees)  :*/
/*::    lat2, lon2 = Latitude and Longitude of point 2 (in decimal degrees)  :*/
/*::    unit = the unit you desire for results                               :*/
/*::           where: 'M' is statute miles                                   :*/
/*::                  'K' is kilometers (default)                            :*/
/*::                  'N' is nautical miles                                  :*/
/*::  Worldwide cities and other features databases with latitude longitude  :*/
/*::  are available at http://www.geodatasource.com                          :*/
/*::                                                                         :*/
/*::  For enquiries, please contact sales@geodatasource.com                  :*/
/*::                                                                         :*/
/*::  Official Web site: http://www.geodatasource.com                        :*/
/*::                                                                         :*/
/*::         GeoDataSource.com (C) All Rights Reserved 2013                  :*/
/*::                                                                         :*/
/*::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::*/
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>";

?>

要查找节点之间的所有距离，您需要简单地遍历所有节点。你会得到一个看起来像这样的数组：

$distance[0][1] = 10;
$distance[0][2] = 12;
$distance[0][3] = 7;
...
$distance[4][3] = 14;

数组的尺寸表示节点编号，指定的值是距离。你将通过Dijkstra运行这个数组来找到最短的加权路径。

希望这会对你有所帮助。如果您需要进一步的帮助，您可能希望尝试将问题缩小到更窄。图遍历是一个非常广泛的研究领域。祝你好运。

使用php的最短路径

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