Example of dynamic data.
Example of dynamic data.
<!DOCTYPE html>
<html>
<head>
<title>Dynamic Data</title>
<link rel="stylesheet" href="https://openlayers.org/en/v5.3.0/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>
</head>
<body>
<div id="map" class="map"></div>
<script>
import Map from 'ol/Map.js';
import View from 'ol/View.js';
import {MultiPoint, Point} from 'ol/geom.js';
import TileLayer from 'ol/layer/Tile.js';
import OSM from 'ol/source/OSM.js';
import {Circle as CircleStyle, Fill, Stroke, Style} from 'ol/style.js';
var map = new Map({
layers: [
new TileLayer({
source: new OSM()
})
],
target: 'map',
view: new View({
center: [0, 0],
zoom: 2
})
});
var imageStyle = new Style({
image: new CircleStyle({
radius: 5,
fill: new Fill({color: 'yellow'}),
stroke: new Stroke({color: 'red', width: 1})
})
});
var headInnerImageStyle = new Style({
image: new CircleStyle({
radius: 2,
fill: new Fill({color: 'blue'})
})
});
var headOuterImageStyle = new Style({
image: new CircleStyle({
radius: 5,
fill: new Fill({color: 'black'})
})
});
var n = 200;
var omegaTheta = 30000; // Rotation period in ms
var R = 7e6;
var r = 2e6;
var p = 2e6;
map.on('postcompose', function(event) {
var vectorContext = event.vectorContext;
var frameState = event.frameState;
var theta = 2 * Math.PI * frameState.time / omegaTheta;
var coordinates = [];
var i;
for (i = 0; i < n; ++i) {
var t = theta + 2 * Math.PI * i / n;
var x = (R + r) * Math.cos(t) + p * Math.cos((R + r) * t / r);
var y = (R + r) * Math.sin(t) + p * Math.sin((R + r) * t / r);
coordinates.push([x, y]);
}
vectorContext.setStyle(imageStyle);
vectorContext.drawGeometry(new MultiPoint(coordinates));
var headPoint = new Point(coordinates[coordinates.length - 1]);
vectorContext.setStyle(headOuterImageStyle);
vectorContext.drawGeometry(headPoint);
vectorContext.setStyle(headInnerImageStyle);
vectorContext.drawGeometry(headPoint);
map.render();
});
map.render();
</script>
</body>
</html>