Show MultiGeometry Data from GeoJSON on the Map

This tutorial shows how to add a GeoJSON MultiGeometry overlay to the map.

  1. Copy the following code, paste it into your favorite text editor, and save it as a .html file.

  2. Replace YOUR_MAPTILER_API_KEY_HERE with your actual MapTiler API key.

  3. The next it’s up to you. You can start the map in a different place by modifying the starting position and starting zoom, and you can change the look of the map to any of our styles, or yours, by updating the style URL. See what’s available here.</li>

  4. Install the npm package.

  5. Include the CSS file in the <head> of your HTML file.

    Including it with a <link> in the head of the document via the CDN is the simplest and easiest way to provide the CSS, but it is also bundled in the MapLibre module, meaning that if you have a bundler that can handle CSS, you can import the CSS from maplibre-gl/dist/maplibre-gl.css.
  6. Include the following code in your JavaScript file (Example: app.js).

  7. Get GeoJSON data hosted on MapTiler Cloud (check out the How to Upload GeoJSON to MapTiler Cloud tutorial). Publish the dataset and copy link to the geojson. Download the sample data here.

    
     map.addControl(new maplibregl.NavigationControl(), 'top-right');
     fetch(`https://api.maptiler.com/data/${dataId}/features.json?key=${key}`).then(function(response) {
         return response.json();
     }).then(function(geojson) {
    
     });
     
  8. Add event handler for map load event. You will add code to create a GeoJSON source and a vector layer in this handler.

    
     .then(function(geojson) {
       map.on('load', function() {
        
       });
     });
     
  9. Create GeoJSON source.

    
       map.on('load', function() {
           map.addSource('geojson-overlay', {
               type: 'geojson',
               data: geojson
           });
       });
     
  10. Add the vector layer. Add a layer for each type of geometry: point, line and polygon

    
       });
       map.addLayer({
         'id': 'geojson-overlay-fill',
         'type': 'fill',
         'source': 'geojson-overlay',
         'filter': ['==', '$type', 'Polygon'],
         'layout': {},
         'paint': {
           'fill-color': '#fff',
           'fill-opacity': 0.4
         }
       });
       map.addLayer({
         'id': 'geojson-overlay-line',
         'type': 'line',
         'source': 'geojson-overlay',
         'layout': {},
         'paint': {
           'line-color': 'rgb(68, 138, 255)',
           'line-width': 3
         }
       });
       map.addLayer({
         'id': 'geojson-overlay-point',
         'type': 'circle',
         'source': 'geojson-overlay',
         'filter': ['==', '$type', 'Point'],
         'layout': {},
         'paint': {
           'circle-color': 'rgb(68, 138, 255)',
           'circle-stroke-color': '#fff',
           'circle-stroke-width': 6,
           'circle-radius': 7
         }
       });
     });
     
  11. Fit the map view to the bounding box of the data.


      const bounds = [Infinity, Infinity, -Infinity, -Infinity];
      const processCoordinates = function(coords) {
          if (Array.isArray(coords[0])) {
              coords.map(c=>processCoordinates(c));
          } else {
              bounds[0] = Math.min(bounds[0], coords[0]);
              bounds[1] = Math.min(bounds[1], coords[1]);
              bounds[2] = Math.max(bounds[2], coords[0]);
              bounds[3] = Math.max(bounds[3], coords[1]);
          }
      };
      geojson.features.forEach(function(f) {
          if (f.geometry && f.geometry.coordinates) {
              processCoordinates(f.geometry.coordinates);
          }
      });
      map.fitBounds(bounds, {
          padding: 20
      });
  

Learn more

Check out the tutorials How to add a GeoJSON in MapLibre (video & code) to learn how to load a point GeoJSON and change the point icon.

JavaScript Maps API

Examples

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