Mapbox-GL Statistics Context
Quantify the reachability - see how many people are within 30 minutes by bike. Drag the marker to see how the reachable population changes
<!DOCTYPE html>
<html>
<head>
<!-- Include mapboxgl javascript and css -->
<script src="https://api.tiles.mapbox.com/mapbox-gl-js/v1.6.0/mapbox-gl.js"></script>
<link href="https://api.tiles.mapbox.com/mapbox-gl-js/v1.6.0/mapbox-gl.css" rel="stylesheet">
<!-- Include targomo core -->
<script src="https://releases.targomo.com/core/latest.min.js"></script>
<!-- Include micro progress bar -->
<script src="https://www.targomo.com/developers/scripts/mipb.min.js"></script>
<style>
body, html {
margin: 0;
width: 100%;
height: 100%;
}
#map {
width: 100%;
height: 100%;
position: relative;
}
.population {
position: absolute; padding: 8px;
top: 10px; left: 10px;
font-family: Helvetica, Arial, Sans-Serif;
background: white; border-radius: 4px;
box-shadow: 0 0 0 2px rgba(0, 0, 0, 0.1);
}
</style>
</head>
<body>
<!-- where the map will live -->
<div id="map"></div>
<div class="population"><span>Reachable Population:</span> <span id="total-pop"></span></div>
<script>
// create targomo client
const client = new tgm.TargomoClient('westcentraleurope', '__targomo_key_here__');
// Coordinates to center the map
const lnglat = [2.374513, 48.844334];
const attributionText = `<a href="https://www.targomo.com/developers/resources/attribution/" target="_blank">© Targomo</a>`;;
// set the progress bar
const pBar = new mipb({ fg: "#FF8319" });
// add the map and set the initial center to paris
const map = new mapboxgl.Map({
container: 'map',
style: 'https://api.maptiler.com/maps/positron/style.json?key=__your_maptiler_api_key__',
minZoom: 9, zoom: 11, center: lnglat, attributionControl: false
}).addControl(new mapboxgl.NavigationControl()).addControl(new mapboxgl.AttributionControl(
{ compact: true, customAttribution: attributionText }
));
// disable scroll zoom
map.scrollZoom.disable();
const marker = new mapboxgl.Marker({
draggable: true
}).setLngLat(lnglat).addTo(map);
marker.on('dragend', getStats);
const stats = {
group: 26,
individual: 8
}
async function getStats() {
// show progress bar
pBar.show();
const sources = [{ ...marker.getLngLat(), id: 1 }];
// reachable stats - returns an object of
// key = statistic cell id, value = travel time to cell centroid
const statistics = await client.statistics.travelTimes(sources, {
maxEdgeWeight: 1800, travelType: "Bike", // 30 minutes on foot
statisticsGroup: stats.group, statistics: [{ id: stats.individual }]
});
// tally full reachable population
const reachablePop = Object.values(statistics).reduce((acc, cur) => acc + cur);
var popElem = document.querySelector('#total-pop');
popElem.innerHTML = reachablePop.toString().replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,');
// only show the cell which are reachable in 30 minutes on foot
map.setFilter("statistics", [
"match", ["get", "id"], Object.keys(statistics).map(k => +k), true, false
]);
// hide progress bar
pBar.hide()
map.on("click", "statistics", (e) => {
const travelTime = Math.round(statistics[e.features[0].properties.id] / 60);
const description = `Population: ${Math.round(e.features[0].properties["8"])}
<br>Bike time: ${travelTime}`;
new mapboxgl.Popup()
.setLngLat(e.lngLat)
.setHTML(description).addTo(map);
});
}
map.on('load', async () => {
// get metadata for statistics group 26 (France INSEE)
// to see the available statistics, as well as details of the dataset
const meta = await client.statistics.metadata(stats.group);
// get details of the population statistics, statistic id 8, of group 26
const populationMeta = await client.statistics.metadataKey(stats.group, { id: stats.individual });
// http://colorbrewer2.org/?type=sequential&scheme=RdPu&n=9
const colors = ['#fff7f3', '#fde0dd', '#fcc5c0', '#fa9fb5', '#f768a1', '#dd3497', '#ae017e', '#7a0177', '#49006a', '#380052'];
const breakpoints = populationMeta.breakpoints.kmeans.c9.map((b, i) => [b, colors[i]]);
const colorDef = ["interpolate", ["linear"], ["get", `${stats.individual}`], ...breakpoints.flat()];
// get the vectortiles url
const tileRoute = await client.statistics.tileRoute(stats.group, [{ id: stats.individual }]);
// add the tiles to the map
map.addLayer({
"id": "statistics",
"type": "fill",
"source": {
"type": "vector",
"tiles": [tileRoute],
"minzoom": meta.min_zoom
},
"source-layer": `${stats.group}`, // source-layer is the statistic group id
"layout": {},
"paint": {
"fill-opacity": 0.6,
"fill-color": colorDef,
"fill-outline-color": "rgba(0,0,0,0)"
}
}, "place_other");
// Change the cursor to a pointer when the mouse is over the stats layer
map.on("mouseenter", "statistics", () => {
map.getCanvas().style.cursor = "pointer";
});
// Change it back to a pointer when it leaves.
map.on("mouseleave", "statistics", () => {
map.getCanvas().style.cursor = "";
});
getStats();
})
</script>
</body>
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