Skip to content

View local GeoJSON

View local GeoJSON without server upload.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>View local GeoJSON</title>
    <meta property="og:description" content="View local GeoJSON without server upload." />
    <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>
    #file {
        position: absolute;
        top: 0;
        left: 0;
    }
</style>
<div id="map"></div>
<input
    type="file"
    id="file"
    name="file"
    accept="application/geo+json,application/vnd.geo+json,.geojson"
/>
<script>
    const map = new maplibregl.Map({
        container: 'map',
        style:
            'https://api.maptiler.com/maps/streets/style.json?key=get_your_own_OpIi9ZULNHzrESv6T2vL',
        center: [-8.3226655, 53.7654751],
        zoom: 8
    });

    function handleFileSelect(evt) {
        const file = evt.target.files[0]; // Read first selected file

        const reader = new FileReader();

        reader.onload = function (theFile) {
            // Parse as (geo)JSON
            const geoJSONcontent = JSON.parse(theFile.target.result);

            // Add as source to the map
            map.addSource('uploaded-source', {
                'type': 'geojson',
                'data': geoJSONcontent
            });

            map.addLayer({
                'id': 'uploaded-polygons',
                'type': 'fill',
                'source': 'uploaded-source',
                'paint': {
                    'fill-color': '#888888',
                    'fill-outline-color': 'red',
                    'fill-opacity': 0.4
                },
                // filter for (multi)polygons; for also displaying linestrings
                // or points add more layers with different filters
                'filter': ['==', '$type', 'Polygon']
            });
        };

        // Read the GeoJSON as text
        reader.readAsText(file, 'UTF-8');
    }

    document
        .getElementById('file')
        .addEventListener('change', handleFileSelect, false);
</script>
</body>
</html>