Google Maps MarkerCluster API:如何在屏幕'视图之外获取集群

Google Maps MarkerCluster API: How to get clusters outside of screen's view?

本文关键字：视图 获取 屏幕 API MarkerCluster Maps Google      更新时间：2023-09-26

我有一个使用谷歌地图和MarkerCluster API的网页。我需要能够得到所有的集群在地图上给定的缩放级别。以以下代码为例:

//Where the center of the screen will be
var center = new google.maps.LatLng(37.4419, -122.1419);
var options = {
  'zoom': 13,
  'center': center,
  //Google map type
  'mapTypeId': google.maps.MapTypeId.ROADMAP
};
//Create the google map
var map = new google.maps.Map(document.getElementById("map"), options);
//Create the marker clusters, where markers is an array of lat and longs
var mc = new MarkerClusterer(map, markers);
//Print all of the clusters at zoom level 13
console.log(mc.getTotalClusters());

问题是，如果缩放级别为13的集群有10个，但只有7个在屏幕的边界内，那么上面的代码只会打印出7个。我需要一种方法来访问所有集群，即使它们不在屏幕上。

MarkerClusterer工作原理的简单例子:https://googlemaps.github.io/js-marker-clusterer/examples/simple_example.html

下面是一些关于MarkerCluster API的引用:

https://googlemaps.github.io/js-marker-clusterer/docs/reference.html

https://googlemaps.github.io/js-marker-clusterer/docs/examples.html

https://developers.google.com/maps/articles/toomanymarkers

实际上，getTotalClusters函数只返回当前视口中可见的标记的群集数量。

获得集群总数的一个选项是通过重写创建集群的函数来禁用检查标记是否位于当前视图内:

MarkerClusterer.prototype.createClusters_ = function() {
  if (!this.ready_) {
    return;
  }
  for (var i = 0, marker; marker = this.markers_[i]; i++) {
    //if (!marker.isAdded && this.isMarkerInBounds_(marker, bounds)) {    
    if (!marker.isAdded) {    
      this.addToClosestCluster_(marker);
    }
  }
};

工作示例

MarkerClusterer.prototype.createClusters_ = function() {
  if (!this.ready_) {
    return;
  }
  for (var i = 0, marker; marker = this.markers_[i]; i++) {
    //if (!marker.isAdded && this.isMarkerInBounds_(marker, bounds)) {    
    if (!marker.isAdded) {    
      this.addToClosestCluster_(marker);
    }
  }
};
function initMap(data) {
    var center = new google.maps.LatLng(59.339025,18.065818);
    var map = new google.maps.Map(document.getElementById('map'), {
        zoom: 5,
        center: center,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    });
 
    var markers = [];
    for (var i = 0; i < data.photos.length; i++) {
        var dataPhoto = data.photos[i];
        var latLng = new google.maps.LatLng(dataPhoto.latitude,dataPhoto.longitude);
        var marker = new google.maps.Marker({
            position: latLng
        });
        markers.push(marker);
    }
    markerCluster = new MarkerClusterer(map, markers, { imagePath: 'https://cdn.rawgit.com/googlemaps/js-marker-clusterer/gh-pages/images/m' });
    google.maps.event.addListenerOnce(map, 'idle', function(){
        console.log("Total number of clusters: " + markerCluster.getTotalClusters());
    });
}
google.maps.event.addDomListener(window, 'load', 
function(){
    $.getJSON("https://gist.githubusercontent.com/vgrem/fb601469049c4be809ad4ea4bbcdc381/raw/data.json")
    .success(function(data) {
        initMap(data);
    });    
});
body {
        margin: 0;
        padding: 10px 20px 20px;
        font-family: Arial;
        font-size: 16px;
      }
      #map-container {
        padding: 6px;
        border-width: 1px;
        border-style: solid;
        border-color: #ccc #ccc #999 #ccc;
        -webkit-box-shadow: rgba(64, 64, 64, 0.5) 0 2px 5px;
        -moz-box-shadow: rgba(64, 64, 64, 0.5) 0 2px 5px;
        box-shadow: rgba(64, 64, 64, 0.1) 0 2px 5px;
        width: 600px;
      }
      #map {
        width: 600px;
        height: 400px;
      }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js"></script>
<script src="https://googlemaps.github.io/js-marker-clusterer/src/markerclusterer.js"></script>
<div id="map-container"><div id="map"></div></div>

恰好

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