Example of drawing arrows for each line string segment.
<!DOCTYPE html> <html> <head> <title>LineString arrows example</title> <script src="https://code.jquery.com/jquery-1.11.2.min.js"></script> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css"> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script> <link rel="stylesheet" href="http://openlayers.org/en/3.8.1/css/ol.css" type="text/css"> <script src="http://openlayers.org/en/3.8.1/build/ol.js"></script> </head> <body> <div class="container-fluid"> <div class="row-fluid"> <div class="span12"> <div id="map" class="map"></div> </div> </div> </div> <script> var raster = new ol.layer.Tile({ source: new ol.source.MapQuest({layer: 'sat'}) }); var source = new ol.source.Vector(); var styleFunction = function(feature, resolution) { 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: 'data/arrow.png', anchor: [0.75, 0.5], rotateWithView: false, 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>