1

我正在检查我们是否可以从 Vector tile 源在 mapbox 端进行聚类，我尝试在后端（POSTGIS）进行聚类，但是大数据表（1M 记录）花费了太多时间。

或者我应该寻找任何其他解决方案。

4

1 回答 1

0

您可以使用Mapbox GL JS在前端聚集大量点。这篇文章包括一个来自 GeoJSON 文件的 400,000 个点的示例，类似的方法应该适用于 1M。Mapbox 网站上有示例代码，我在下面复制了这些代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Create and style clusters</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://api.mapbox.com/mapbox-gl-js/v1.9.1/mapbox-gl.js"></script>
<link href="https://api.mapbox.com/mapbox-gl-js/v1.9.1/mapbox-gl.css" rel="stylesheet" />
<style>
	body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<div id="map"></div>

<script>
	mapboxgl.accessToken = 'pk.eyJ1IjoicGxtYXBib3giLCJhIjoiY2s2MThyOG9vMDEydjNrcGplNzZiMXJ2NyJ9.KJn6ZtoogD-QMm80LonTzA';
    var map = new mapboxgl.Map({
        container: 'map',
        style: 'mapbox://styles/mapbox/dark-v10',
        center: [-103.59179687498357, 40.66995747013945],
        zoom: 3
    });

    map.on('load', function() {
        // Add a new source from our GeoJSON data and
        // set the 'cluster' option to true. GL-JS will
        // add the point_count property to your source data.
        map.addSource('earthquakes', {
            type: 'geojson',
            // Point to GeoJSON data. This example visualizes all M1.0+ earthquakes
            // from 12/22/15 to 1/21/16 as logged by USGS' Earthquake hazards program.
            data:
                'https://docs.mapbox.com/mapbox-gl-js/assets/earthquakes.geojson',
            cluster: true,
            clusterMaxZoom: 14, // Max zoom to cluster points on
            clusterRadius: 50 // Radius of each cluster when clustering points (defaults to 50)
        });

        map.addLayer({
            id: 'clusters',
            type: 'circle',
            source: 'earthquakes',
            filter: ['has', 'point_count'],
            paint: {
                // Use step expressions (https://docs.mapbox.com/mapbox-gl-js/style-spec/#expressions-step)
                // with three steps to implement three types of circles:
                //   * Blue, 20px circles when point count is less than 100
                //   * Yellow, 30px circles when point count is between 100 and 750
                //   * Pink, 40px circles when point count is greater than or equal to 750
                'circle-color': [
                    'step',
                    ['get', 'point_count'],
                    '#51bbd6',
                    100,
                    '#f1f075',
                    750,
                    '#f28cb1'
                ],
                'circle-radius': [
                    'step',
                    ['get', 'point_count'],
                    20,
                    100,
                    30,
                    750,
                    40
                ]
            }
        });

        map.addLayer({
            id: 'cluster-count',
            type: 'symbol',
            source: 'earthquakes',
            filter: ['has', 'point_count'],
            layout: {
                'text-field': '{point_count_abbreviated}',
                'text-font': ['DIN Offc Pro Medium', 'Arial Unicode MS Bold'],
                'text-size': 12
            }
        });

        map.addLayer({
            id: 'unclustered-point',
            type: 'circle',
            source: 'earthquakes',
            filter: ['!', ['has', 'point_count']],
            paint: {
                'circle-color': '#11b4da',
                'circle-radius': 4,
                'circle-stroke-width': 1,
                'circle-stroke-color': '#fff'
            }
        });

        // inspect a cluster on click
        map.on('click', 'clusters', function(e) {
            var features = map.queryRenderedFeatures(e.point, {
                layers: ['clusters']
            });
            var clusterId = features[0].properties.cluster_id;
            map.getSource('earthquakes').getClusterExpansionZoom(
                clusterId,
                function(err, zoom) {
                    if (err) return;

                    map.easeTo({
                        center: features[0].geometry.coordinates,
                        zoom: zoom
                    });
                }
            );
        });
        
        // When a click event occurs on a feature in
        // the unclustered-point layer, open a popup at
        // the location of the feature, with
        // description HTML from its properties.
        map.on('click', 'unclustered-point', function(e) {

            var coordinates = e.features[0].geometry.coordinates.slice();
            var mag = e.features[0].properties.mag;
            var tsunami;
            
            if (e.features[0].properties.tsunami === 1) {
                tsunami = 'yes'
            } else {
                tsunami = 'no'
            }

            // Ensure that if the map is zoomed out such that
            // multiple copies of the feature are visible, the
            // popup appears over the copy being pointed to.
            while (Math.abs(e.lngLat.lng - coordinates[0]) > 180) {
                coordinates[0] += e.lngLat.lng > coordinates[0] ? 360 : -360;
            }

            new mapboxgl.Popup()
                .setLngLat(coordinates)
                .setHTML("magnitude: " + mag + "<br>Was there a tsunami?: " + tsunami)
                .addTo(map);
        });

        map.on('mouseenter', 'clusters', function() {
            map.getCanvas().style.cursor = 'pointer';
        });
        map.on('mouseleave', 'clusters', function() {
            map.getCanvas().style.cursor = '';
        });
    });
</script>

</body>
</html>

于 2020-04-10T14:12:26.087 回答