MapBox - Cluster Zooming

问题

Is it possible to recreate the click to zoom on clustering like Craigslist Mapview does with MapBox? When you click, it zooms to the area those location dots are contained in.

Here's my clustering code:

map.on('load', function() {
map.addSource("location", {
    type: "geojson",
    data: "https://s3-us-west-2.amazonaws.com/s.cdpn.io/73873/test.geojson",
    cluster: true,
    clusterMaxZoom: 14,
    clusterRadius: 100
});

    map.addLayer({
    id: "clusters",
    type: "circle",
    source: "location",
    filter: ["has", "point_count"],
    paint: {
        "circle-color": {
            property: "point_count",
            type: "interval",
            stops: [
                [0, "#71AAC6"],
                [100, "#71AAC6"],
                [750, "#71AAC6"],
            ]
        },
        "circle-radius": {
            property: "point_count",
            type: "interval",
            stops: [
                [0, 20],
                [100, 30],
                [750, 40]
            ]
        }
    }
});

Here's my demo

Codepen Demo

回答1:

As @MeltedPenguin said. You can do it without SuperCluster. I search for several answers and finally did my own solution using coffeescript (you can convert it back to JS with tools like http://js2.coffee/):

    @clusterRadius = 30
    @map.on 'click', (e) =>
          features = @map.queryRenderedFeatures(e.point, { layers: ['markers_layer'] });
          if features && features.length > 0
            if features[0].properties.cluster
              cluster = features[0].properties

              allMarkers = @map.queryRenderedFeatures(layers:['markers_layer_dot']);
              self = @ #just a way to use 'this' un a function, its more verbose then =>    

              #Get all Points of a Specific Cluster
              pointsInCluster = allMarkers.filter((mk) ->
                pointPixels = self.map.project(mk.geometry.coordinates) #get the point pixel
                #Get the distance between the Click Point and the Point we are evaluating from the Matrix of All point
                pixelDistance = Math.sqrt((e.point.x - (pointPixels.x)) ** 2 + (e.point.y - (pointPixels.y)) ** 2)

                #If the distant is greater then the disance that define a cluster,  then the point si in the cluster
                # add it to the boundaries
                Math.abs(pixelDistance) <= self.clusterRadius
              )

              #build the bounding box with the selected points coordinates
              bounds = new (mapboxgl.LngLatBounds)
              pointsInCluster.forEach (feature) ->
                bounds.extend feature.geometry.coordinates
                return

              #Move the map to fit the Bounding Box (BBox)
              @map.fitBounds bounds, {padding:45, maxZoom: 16}

            else
              window.open('/en/ad/' + features[0].properties.propertyId)

On my page I have 2 layers based on the same source of data but with different attributes. One that define all dots (without clusters) and another one which define dots and clusters. For my display I use the "markers_layer" with clusters, and for calculate distance and stuff I use the other, as a DB of dots.

SOURCE:

  @map.addSource "markers_source_wo_cluster",
    type: "geojson"
    data:
      type: "FeatureCollection"
      features: []
    cluster: false
    clusterMaxZoom: 10
    clusterRadius: @clusterRadius

  @map.addSource "markers_source",
    type: "geojson"
    data:
      type: "FeatureCollection"
      features: []
    cluster: true
    clusterMaxZoom: 60
    clusterRadius: @clusterRadius

LAYER:

##============================================================##
## Add marker layer (Layer for QueryRender all dot without cluster)
##============================================================##
@map.addLayer
  id: 'markers_layer_dot'
  source: 'markers_source_wo_cluster'
  type: "circle"
  paint:
    "circle-radius": 0 #This are 1 pixel dot for ref only

##============================================================##
## Add marker layer
##============================================================##
@map.addLayer
  id: 'markers_layer'
  source: 'markers_source'
  type: 'symbol'
  layout:
    'icon-allow-overlap': true
    'icon-image':'pin_map'
    'icon-size':
      stops: [[0,0.4], [40,0.4]]

回答2:

I don't think that you can do it in pure Mapbox, at least not easily.

But for those cluster specific usages there is Supercluster (an official Mapbox geospatial point clustering library) which has exactly what you want:

getClusterExpansionZoom(clusterId)

Returns the zoom on which the cluster expands into several children (useful for "click to zoom" feature) given the cluster's cluster_id.

Edit: actually you could do it without Supercluster:

Using this JsFiddle example you can retrieve the points of the cluster you clicked.

map.on('click', function(e) {
    const cluster = map.queryRenderedFeatures(e.point, { layers: ["cluster"] });

    if (cluster[0]) {
    // features: from the added source that are clustered
    const pointsInCluster = features.filter(f => {
        const pointPixels = map.project(f.geometry.coordinates)
      const pixelDistance = Math.sqrt(
        Math.pow(e.point.x - pointPixels.x, 2) + 
        Math.pow(e.point.y - pointPixels.y, 2) 
      );
      return Math.abs(pixelDistance) <= clusterRadius;
    });
    console.log(cluster, pointsInCluster);
  }
});

Then you can create a mapboxgl.LngLatBounds and extend it with all those points.
You will obtain a LngLatBounds wrapping all your points so you can just call fitBounds on it and you are good to go.

来源：https://stackoverflow.com/questions/48232134/mapbox-cluster-zooming

标签

javascript

mapbox

mapbox-gl