LineString Arrows

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

#### LineString Arrows

Example of drawing arrows for each line string segment.

Example of drawing arrows for each line string segment.

Related API documentation:

- ol.Map
,
- ol.View
,
- ol.geom.Point
,
- ol.interaction.Draw
,
- ol.layer.Tile
,
- ol.layer.Vector
,
- ol.source.OSM
,
- ol.source.Vector
,
- ol.style.Icon
,
- ol.style.Stroke
,
- ol.style.Style

Copy Edit
LineString Arrows Example of drawing arrows for each line string segment. var raster = new ol.layer.Tile({ source: new ol.source.OSM() }); var source = new ol.source.Vector(); var styleFunction = function(feature) { var geometry = feature.getGeometry(); var styles = [ // linestring new ol.style.Style({ stroke: new ol.style.Stroke({ color: '#ffcc33', width: 2 }) }) ]; geometry.forEachSegment(function(start, end) { var dx = end[0] - start[0]; var dy = end[1] - start[1]; var rotation = Math.atan2(dy, dx); // arrows styles.push(new ol.style.Style({ geometry: new ol.geom.Point(end), image: new ol.style.Icon({ src: 'https://openlayers.org/en/v4.0.1/examples/data/arrow.png', anchor: [0.75, 0.5], rotateWithView: true, rotation: -rotation }) })); }); return styles; }; var vector = new ol.layer.Vector({ source: source, style: styleFunction }); var map = new ol.Map({ layers: [raster, vector], target: 'map', view: new ol.View({ center: [-11000000, 4600000], zoom: 4 }) }); map.addInteraction(new ol.interaction.Draw({ source: source, type: /** @type {ol.geom.GeometryType} */ ('LineString') })); <div id="map" class="map"></div>

    <!DOCTYPE html>
    <html>
      <head>
        <title>LineString Arrows</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>
      </head>
      <body>
        <div id="map" class="map"></div>
        <script>
          var raster = new ol.layer.Tile({
            source: new ol.source.OSM()
          });

          var source = new ol.source.Vector();

          var styleFunction = function(feature) {
            var geometry = feature.getGeometry();
            var styles = [
              // linestring
              new ol.style.Style({
                stroke: new ol.style.Stroke({
                  color: '#ffcc33',
                  width: 2
                })
              })
            ];

            geometry.forEachSegment(function(start, end) {
              var dx = end[0] - start[0];
              var dy = end[1] - start[1];
              var rotation = Math.atan2(dy, dx);
              // arrows
              styles.push(new ol.style.Style({
                geometry: new ol.geom.Point(end),
                image: new ol.style.Icon({
                  src: 'https://openlayers.org/en/v4.0.1/examples/data/arrow.png',
                  anchor: [0.75, 0.5],
                  rotateWithView: true,
                  rotation: -rotation
                })
              }));
            });

            return styles;
          };
          var vector = new ol.layer.Vector({
            source: source,
            style: styleFunction
          });

          var map = new ol.Map({
            layers: [raster, vector],
            target: 'map',
            view: new ol.View({
              center: [-11000000, 4600000],
              zoom: 4
            })
          });

          map.addInteraction(new ol.interaction.Draw({
            source: source,
            type: /** @type {ol.geom.GeometryType} */ ('LineString')
          }));
        </script>
      </body>
    </html>