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Create a time slider

Visualize earthquakes with a range slider.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Create a time slider</title>
    <meta property="og:description" content="Visualize earthquakes with a range slider." />
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel='stylesheet' href='https://unpkg.com/maplibre-gl@4.4.1/dist/maplibre-gl.css' />
    <script src='https://unpkg.com/maplibre-gl@4.4.1/dist/maplibre-gl.js'></script>
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
    </style>
</head>
<body>
<style>
    .map-overlay {
        font: 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
        position: absolute;
        width: 25%;
        top: 0;
        left: 0;
        padding: 10px;
    }

    .map-overlay .map-overlay-inner {
        background-color: #fff;
        box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
        border-radius: 3px;
        padding: 10px;
        margin-bottom: 10px;
    }

    .map-overlay h2 {
        line-height: 24px;
        display: block;
        margin: 0 0 10px;
    }

    .map-overlay .legend .bar {
        height: 10px;
        width: 100%;
        background: linear-gradient(to right, #fca107, #7f3121);
    }

    .map-overlay input {
        background-color: transparent;
        display: inline-block;
        width: 100%;
        position: relative;
        margin: 0;
        cursor: ew-resize;
    }
</style>

<div id="map"></div>

<div class="map-overlay top">
    <div class="map-overlay-inner">
        <h2>Significant earthquakes in 2015</h2>
        <label id="month" for="slider"></label>
        <input id="slider" type="range" min="0" max="11" step="1" value="0" />
    </div>
    <div class="map-overlay-inner">
        <div id="legend" class="legend">
            <div class="bar"></div>
            <div>Magnitude (m)</div>
        </div>
    </div>
</div>

<script src="https://d3js.org/d3.v3.min.js" charset="utf-8"></script>
<script>
    const map = new maplibregl.Map({
        container: 'map',
        style:
            'https://api.maptiler.com/maps/streets/style.json?key=get_your_own_OpIi9ZULNHzrESv6T2vL',
        center: [31.4606, 20.7927],
        zoom: 0.5
    });

    const months = [
        'January',
        'February',
        'March',
        'April',
        'May',
        'June',
        'July',
        'August',
        'September',
        'October',
        'November',
        'December'
    ];

    function filterBy(month) {
        const filters = ['==', 'month', month];
        map.setFilter('earthquake-circles', filters);
        map.setFilter('earthquake-labels', filters);

        // Set the label to the month
        document.getElementById('month').textContent = months[month];
    }

    map.on('load', () => {
        // Data courtesy of https://www.usgs.gov/programs/earthquake-hazards
        // Query for significant earthquakes in 2015 URL request looked like this:
        // https://earthquake.usgs.gov/fdsnws/event/1/query
        //    ?format=geojson
        //    &starttime=2015-01-01
        //    &endtime=2015-12-31
        //    &minmagnitude=6'
        //
        // Here we're using d3 to help us make the ajax request but you can use
        // Any request method (library or otherwise) you wish.
        d3.json(
            'https://maplibre.org/maplibre-gl-js/docs/assets/significant-earthquakes-2015.geojson',
            (err, data) => {
                if (err) throw err;

                // Create a month property value based on time
                // used to filter against.
                data.features = data.features.map((d) => {
                    d.properties.month = new Date(d.properties.time).getMonth();
                    return d;
                });

                map.addSource('earthquakes', {
                    'type': 'geojson',
                    data
                });

                map.addLayer({
                    'id': 'earthquake-circles',
                    'type': 'circle',
                    'source': 'earthquakes',
                    'paint': {
                        'circle-color': [
                            'interpolate',
                            ['linear'],
                            ['get', 'mag'],
                            6,
                            '#FCA107',
                            8,
                            '#7F3121'
                        ],
                        'circle-opacity': 0.75,
                        'circle-radius': [
                            'interpolate',
                            ['linear'],
                            ['get', 'mag'],
                            6,
                            20,
                            8,
                            40
                        ]
                    }
                });

                map.addLayer({
                    'id': 'earthquake-labels',
                    'type': 'symbol',
                    'source': 'earthquakes',
                    'layout': {
                        'text-field': [
                            'concat',
                            ['to-string', ['get', 'mag']],
                            'm'
                        ],
                        'text-font': [
                            'Open Sans Bold',
                            'Arial Unicode MS Bold'
                        ],
                        'text-size': 12
                    },
                    'paint': {
                        'text-color': 'rgba(0,0,0,0.5)'
                    }
                });

                // Set filter to first month of the year
                // 0 = January
                filterBy(0);

                document
                    .getElementById('slider')
                    .addEventListener('input', (e) => {
                        const month = parseInt(e.target.value, 10);
                        filterBy(month);
                    });
            }
        );
    });
</script>
</body>
</html>