php - 服务器端集群谷歌地图标记

Question

我想知道在 PHP 中聚类标记最快的算法是什么？

我唯一需要的集群函数是带有集群 obj 的输出，它具有以下属性:lat、lng 和 size。

当然还有没有聚类的标记，但我似乎找不到这方面的 php 代码，但一定有一些？

我正在寻找会产生这种结果的代码隐藏？ (或者可能表现更好)。 http://maps.forum.nu/server_side_clusterer/

到目前为止，我尝试过:

function ClusterMarkers($markers,$ZOOM)
  {
  $this->load->library('firephp');    
  $singleMarkers = array();
  $clusterMarkers = array();

  // Minimum distance between markers to be included in a cluster, at diff. zoom levels
  $DISTANCE = (10000000 >> $ZOOM);
  // Loop until all markers have been compared.
  while (count($markers)) {
      $marker  = array_pop($markers);
      $cluster = array();

      // Compare against all markers which are left.
      foreach ($markers as $key => $target) {
          $pixels = abs($marker['lat']-$target['lat']) + abs($marker['lng']-$target['lng']);
          $this->firephp->log('pix :'.$pixels);
          if ($pixels < $DISTANCE) {
              unset($markers[$key]);
              $cluster[] = $target;
          }
      }

      // If a marker has been added to cluster, add also the one we were comparing to.
      if (count($cluster) > 0) {
          $cluster[] = $marker;
          $clusterMarkers[] = $cluster;
      } else {
          $singleMarkers[] = $marker;
      }
  } 
  return array('singlemarkers' => $singleMarkers, 'clustermarkers' => $clusterMarkers); 
  }

然后我的数据被 json 化，但 clustermarkers 数组包含所有标记数据，我想知道我如何有效地简单地设置纬度、经度和大小，而不必在每次添加新标记时重新计算资源需求。

Answer 1

$clusterMarkers 数组基本上是一组聚类标记，因此您可以简单地获取包含标记的质心，而不是返回所有标记。在返回结果之前，做:

foreach($clusterMarkers as $key => $cluster) {
    $centroid = array('lat' => 0, 'lng' => 0, 'count' => 0);
    foreach($cluster as $marker) {    
        $centroid['lat'] += $marker['lat']; // Sum up the Lats
        $centroid['lng'] += $marker['lng']; // Sum up the Lngs
        $centroid['count']++;
    }
    $centroid['lat'] /= $centroid['count']; // Average Lat
    $centroid['lng'] /= $centroid['count']; // Average Lng
    $clusterMarkers[$key] = $centroid; // Overwrite the cluster with the single point.
}