[GIS] Toggling multiple layers with one click? Mapbox GL JS

javascriptlayersmapbox-gl-js

How would I go about grouping the two layers in the sample code below so they could be toggled on and off together with one button? 

<html>
<head>
    <meta charset='utf-8' />
    <title></title>
    <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
    <script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.22.1/mapbox-gl.js'></script>
    <link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.22.1/mapbox-gl.css' rel='stylesheet' />
    <style>
        body { margin:0; padding:0; }
        #map { position:absolute; top:0; bottom:0; width:100%; }
    </style>
</head>
<body>

<style>
    #menu {
        background: #fff;
        position: absolute;
        z-index: 1;
        top: 10px;
        right: 10px;
        border-radius: 3px;
        width: 120px;
        border: 1px solid rgba(0,0,0,0.4);
        font-family: 'Open Sans', sans-serif;
    }

    #menu a {
        font-size: 13px;
        color: #404040;
        display: block;
        margin: 0;
        padding: 0;
        padding: 10px;
        text-decoration: none;
        border-bottom: 1px solid rgba(0,0,0,0.25);
        text-align: center;
    }

    #menu a:last-child {
        border: none;
    }

    #menu a:hover {
        background-color: #f8f8f8;
        color: #404040;
    }

    #menu a.active {
        background-color: #3887be;
        color: #ffffff;
    }

    #menu a.active:hover {
        background: #3074a4;
    }
</style>

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

<script>
mapboxgl.accessToken = 'pk.eyJ1IjoiZnJlZWFjY291bnQxIiwiYSI6ImNpZmFqZm53NDJmNXhzbWx4dXM5bm1leDMifQ.MMgR4bJlNNVYrzCLA_NBeA';
var map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/mapbox/streets-v9',
    zoom: 15,
    center: [-71.97722138410576, -13.517379300798098]
});

map.on('load', function () {
    map.addSource('museums', {
        type: 'vector',
        url: 'mapbox://mapbox.2opop9hr'
    });
    map.addLayer({
        'id': 'museums',
        'type': 'circle',
        'source': 'museums',
        'layout': {
            'visibility': 'visible'
        },
        'paint': {
            'circle-radius': 8,
            'circle-color': 'rgba(55,148,179,1)'
        },
        'source-layer': 'museum-cusco'
    });

    map.addSource('contours', {
        type: 'vector',
        url: 'mapbox://mapbox.mapbox-terrain-v2'
    });
    map.addLayer({
        'id': 'contours',
        'type': 'line',
        'source': 'contours',
        'source-layer': 'contour',
        'layout': {
            'visibility': 'visible',
            'line-join': 'round',
            'line-cap': 'round'
        },
        'paint': {
            'line-color': '#877b59',
            'line-width': 1
        }
    });
});

var toggleableLayerIds = [ 'contours', 'museums' ];

for (var i = 0; i < toggleableLayerIds.length; i++) {
    var id = toggleableLayerIds[i];

    var link = document.createElement('a');
    link.href = '#';
    link.className = 'active';
    link.textContent = id;

    link.onclick = function (e) {
        var clickedLayer = this.textContent;
        e.preventDefault();
        e.stopPropagation();

        var visibility = map.getLayoutProperty(clickedLayer, 'visibility');

        if (visibility === 'visible') {
            map.setLayoutProperty(clickedLayer, 'visibility', 'none');
            this.className = '';
        } else {
            this.className = 'active';
            map.setLayoutProperty(clickedLayer, 'visibility', 'visible');
        }
    };

    var layers = document.getElementById('menu');
    layers.appendChild(link);
}

</script>

</body>
</html>

Best Answer

It's as simple as iterating the toggleableLayerIds array and toggle on and off the layers. Move the link stuff outside the for loop to get just a single button.

var toggleableLayerIds = [ 'contours', 'museums' ];

var link = document.createElement('a');
link.href = '#';
link.className = 'active';
link.textContent = "toggle layers";
link.onclick = function (e) {
    for(var index in toggleableLayerIds) {
      var clickedLayer = toggleableLayerIds[index];
      e.preventDefault();
      e.stopPropagation();

      var visibility = map.getLayoutProperty(clickedLayer, 'visibility');

      if (visibility === 'visible') {
          map.setLayoutProperty(clickedLayer, 'visibility', 'none');
          this.className = '';
      } else {
          this.className = 'active';
          map.setLayoutProperty(clickedLayer, 'visibility', 'visible');
      }
    }

};
var layers = document.getElementById('menu');
layers.appendChild(link);

Demo: https://plnkr.co/edit/HxV766XO1F8FXZbUqRNh?p=preview

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