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Use a fallback image

Use a fallback image

Use a coalesce expression to display another image when a requested image is not available.

Use a fallback image
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Use a fallback image</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://cdn.jsdelivr.net/npm/@goongmaps/goong-js@1.0.9/dist/goong-js.js"></script>
<link href="https://cdn.jsdelivr.net/npm/@goongmaps/goong-js@1.0.9/dist/goong-js.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>
    goongjs.accessToken = 'wnicbAmnNkoMHNYUKWnlFHezV189FjmMwkNJ7hKW';
    var map = new goongjs.Map({
        container: 'map',
        style: 'https://tiles.goong.io/assets/goong_map_web.json',
        center: [-77, 38.75],
        zoom: 5
    });
    map.on('load', function () {
        map.addSource('points', {
            'type': 'geojson',
            'data': {
                'type': 'FeatureCollection',
                'features': [
                    {
                        'type': 'Feature',
                        'geometry': {
                            'type': 'Point',
                            'coordinates': [
                                -77.03238901390978, 38.913188059745586
                            ]
                        },
                        'properties': {
                            'title': 'Washington DC',
                            'icon': 'monument'
                        }
                    },
                    {
                        'type': 'Feature',
                        'geometry': {
                            'type': 'Point',
                            'coordinates': [-79.9959, 40.4406]
                        },
                        'properties': {
                            'title': 'Pittsburgh',
                            'icon': 'golf'
                        }
                    },
                    {
                        'type': 'Feature',
                        'geometry': {
                            'type': 'Point',
                            'coordinates': [-76.2859, 36.8508]
                        },
                        'properties': {
                            'title': 'Norfolk',
                            'icon': 'harbor'
                        }
                    }
                ]
            }
        });
        map.addLayer({
            'id': 'points',
            'type': 'symbol',
            'source': 'points',
            'layout': {
                'icon-image': [
                    'coalesce',
                    ['image', ['concat', ['get', 'icon'], '-15']],
                    ['image', 'marker_15']
                ],
                'text-field': ['get', 'title'],
                'text-font': ['Roboto Regular'],
                'text-offset': [0, 0.6],
                'text-anchor': 'top'
            }
        });
    });
</script>
</body>
</html>