turf.js

This example uses OpenLayers v4.0.1. The latest is v.

#### turf.js

Example on how to use turf.js with OpenLayers.

Example showing the integration of turf.js with OpenLayers. The turf.js function `along` is used to display a marker every 200 meters along a street.

Related API documentation:

- ol.Map
,
- ol.View
,
- ol.format.GeoJSON
,
- ol.layer.Tile
,
- ol.layer.Vector
,
- ol.proj
,
- ol.source.OSM
,
- ol.source.Vector

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turf.js Example on how to use turf.js with OpenLayers. // this example uses turf.js for which we don't have an externs file. var source = new ol.source.Vector(); fetch('https://openlayers.org/en/v4.0.1/examples/data/geojson/roads-seoul.geojson').then(function(response) { return response.json(); }).then(function(json) { var format = new ol.format.GeoJSON(); var features = format.readFeatures(json); var street = features[0]; // convert to a turf.js feature var turfLine = format.writeFeatureObject(street); // show a marker every 200 meters var distance = 0.2; // get the line length in kilometers var length = turf.lineDistance(turfLine, 'kilometers'); for (var i = 1; i <= length / distance; i++) { var turfPoint = turf.along(turfLine, i * distance, 'kilometers'); // convert the generated point to a OpenLayers feature var marker = format.readFeature(turfPoint); marker.getGeometry().transform('EPSG:4326', 'EPSG:3857'); source.addFeature(marker); } street.getGeometry().transform('EPSG:4326', 'EPSG:3857'); source.addFeature(street); }); var vectorLayer = new ol.layer.Vector({ source: source }); var rasterLayer = new ol.layer.Tile({ source: new ol.source.OSM() }); var map = new ol.Map({ layers: [rasterLayer, vectorLayer], target: document.getElementById('map'), view: new ol.View({ center: ol.proj.fromLonLat([126.980366, 37.526540]), zoom: 15 }) }); <div id="map" class="map"></div>

    <!DOCTYPE html>
    <html>
      <head>
        <title>turf.js</title>
        <link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/css/ol.css" type="text/css">
        <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
        <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
        <script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
        <script src="https://api.tiles.mapbox.com/mapbox.js/plugins/turf/v2.0.0/turf.min.js"></script>
      </head>
      <body>
        <div id="map" class="map"></div>
        <script>
          // this example uses turf.js for which we don't have an externs file.
          var source = new ol.source.Vector();
          fetch('https://openlayers.org/en/v4.0.1/examples/data/geojson/roads-seoul.geojson').then(function(response) {
            return response.json();
          }).then(function(json) {
            var format = new ol.format.GeoJSON();
            var features = format.readFeatures(json);
            var street = features[0];

            // convert to a turf.js feature
            var turfLine = format.writeFeatureObject(street);

            // show a marker every 200 meters
            var distance = 0.2;

            // get the line length in kilometers
            var length = turf.lineDistance(turfLine, 'kilometers');
            for (var i = 1; i <= length / distance; i++) {
              var turfPoint = turf.along(turfLine, i * distance, 'kilometers');

              // convert the generated point to a OpenLayers feature
              var marker = format.readFeature(turfPoint);
              marker.getGeometry().transform('EPSG:4326', 'EPSG:3857');
              source.addFeature(marker);
            }

            street.getGeometry().transform('EPSG:4326', 'EPSG:3857');
            source.addFeature(street);
          });
          var vectorLayer = new ol.layer.Vector({
            source: source
          });

          var rasterLayer = new ol.layer.Tile({
            source: new ol.source.OSM()
          });

          var map = new ol.Map({
            layers: [rasterLayer, vectorLayer],
            target: document.getElementById('map'),
            view: new ol.View({
              center: ol.proj.fromLonLat([126.980366, 37.526540]),
              zoom: 15
            })
          });
        </script>
      </body>
    </html>