Clustering GeoJSON - best practice?

[Michal Zimmermann]

Hi,
I've got thousands of points saved in geojson file. I'd like to cluster them with L.markerClusterGroup and yet have the option to toggle them separately in the layers control. You can see what I've tried so far in the code below.

json = L.geoJson(data, {
        onEachFeature: function(feature, layer) {
            layer.bindPopup(L.Util.template("<h1>{title}</h1><p>{description}</p>", {
                title: feature.properties.title,
                description: feature.properties.description
            }));

            category = feature.properties.location_type;

            if (typeof categories[category] == "undefined") {
                categories[category] = [];
            }

            categories[category].push(layer);
        },
        pointToLayer: function(feature, position) {
            return L.marker(position, {icon: L.AwesomeMarkers.icon(styles[feature.properties.location_type])});
        }
    });

    cluster = L.markerClusterGroup({
        chunkedLoading: true,
        chunkInterval: 500
    });
    cluster.addTo(map);

    map.on("overlayadd", function(e) {
        map.removeLayer(e.layer);
        cluster.addLayer(e.layer);
    })

    map.on("overlayremove", function(e) {
        cluster.removeLayer(e.layer);
    })

    for (var category in categories) {
        overlays[styles[category].type] = L.layerGroup(categories[category]);
    }

The performance is really poor due to what happens when overlay is added to the map. I haven't found a way to supress default behavior of map.overlayadd event. Is there any way to add layer to the cluster without letting it into the map itself?

[Anika Halota]

I can't see in the code you posted where you are adding the layers to the map. Can you post more of it or better yet create a https://jsfiddle.net/ with a subset of your data ?

[Michal Zimmermann]

Here you go: https://jsfiddle.net/m2esb2k0/

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Michal Zimmermann (zimmi) 
WWW: http://www.zimmi.cz

[ghybs]

Hi,

I think you would be interested in that post:
https://gis.stackexchange.com/questions/169011/leaflet-how-to-create-toggleable-overlays-from-a-single-geojson-featurecollecti/169038#169038

I also just released 2 plugins that I think would fit your need:
- Leaflet.FeatureGroup.SubGroup Creates a Feature Group that adds its child layers into a parent group when added to a map (e.g. through L.Control.Layers). Typical usage is to dynamically add/remove groups of markers from Marker Cluster.
- Leaflet.MarkerCluster.LayerSupport Brings compatibility with L.Control.Layers and other Leaflet plugins. I.e. everything that uses direct calls to map.addLayer and map.removeLayer.

Hope this helps.

[Michal Zimmermann]

Hi,

I've just implemented subgroup today to my code and it's great! Thanks a lot.