turf-bearing
Calculates the bearing between two point features in degrees.
<!doctype html>
<html lang="en">
<head>
<link rel="stylesheet" href="https://rawcdn.githack.com/openlayers/openlayers.github.io/master/en/v5.3.0/css/ol.css" type="text/css">
<link rel="stylesheet" href="assets/css/styles.css" type="text/css">
<script src="//cdn.jsdelivr.net/npm/@turf/turf@5/turf.min.js"></script>
<script src="https://rawcdn.githack.com/openlayers/openlayers.github.io/master/en/v5.3.0/build/ol.js" type="text/javascript"></script>
<title>Turf and OpenLayers 3 - bearing</title>
</head>
<body>
<div id="map" class="map"></div>
<div id="bearing"></div>
<script type="text/javascript">
var x1 = -1.5741021;
var y1 = 47.1991929;
// Cranes of Nantes with properties defined
var pt1 = turf.point([x1, y1], {
name: 'Grue grise',
man_made: 'crane'
});
var x2 = -1.57007;
var y2 = 47.20507;
var pt2 = turf.point([x2, y2], {
name: 'Grue jaune',
man_made: 'crane'
});
var fc = turf.featureCollection([pt1, pt2]);
var bearing = turf.bearing(pt1, pt2);
// Declare a source
var vectorSource = new ol.source.Vector();
// When reading feature, reproject to EPSG 3857
var features = (new ol.format.GeoJSON()).readFeatures(fc, {
featureProjection: 'EPSG:3857'
});
// Add a feature
vectorSource.addFeatures(features);
var pointsStyle = [new ol.style.Style({
image: new ol.style.Circle({
stroke: new ol.style.Stroke({
color: 'white'
}),
fill: new ol.style.Fill({
color: '#1f6b75'
}),
radius: 5
})
})];
// Declare a vector layer with the already
// created source containing added features
var vectorLayer = new ol.layer.Vector({
source: vectorSource,
style: pointsStyle
});
var vectorLine = new ol.layer.Vector({
source: new ol.source.Vector({
features: (new ol.format.GeoJSON()).readFeatures(
turf.lineString([[x1, y1], [x2, y2]], {}), {
featureProjection: 'EPSG:3857'
}
),
projection: 'EPSG:3857'
}),
style: [
new ol.style.Style({
stroke: new ol.style.Stroke({
color: 'white',
width: 3
})
}),
new ol.style.Style({
stroke: new ol.style.Stroke({
color: [0, 121, 88, 1],
width: 1
})
})
]
});
// Instanciate a map and add layers
var map = new ol.Map({
target: 'map',
layers: [
new ol.layer.Tile({
source: new ol.source.OSM()
}),
vectorLine,
vectorLayer
],
view: new ol.View({
center: ol.proj.transform(
[-1.571456, 47.202561],
'EPSG:4326',
'EPSG:3857'
),
zoom: 15
})
});
var bearingElement = document.getElementById('bearing');
bearingElement.innerHTML = Math.round(bearing * 1000) / 1000;
</script>
</body>
</html>