turf-bboxPolygon
Takes a bbox and returns the equivalent polygon feature.
<!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"></script>
<script src="assets/js/es6-promise.min.js"></script>
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL,fetch"></script>
<script src="assets/js/helpers.js"></script>
<title>Turf and OpenLayers 3 - BboxPolygon</title>
</head>
<body>
<div id="map" class="map"></div>
<button id="createbboxpolygon" type="button">
Generate random bboxpolygon from existing area
</button>
<script type="text/javascript">
function getRandomInt(min, max) {
return Math.floor(Math.random() * (max - min + 1)) + min;
}
// Declare a source for polygons
var vectorSourcePolygons = new ol.source.Vector();
var vectorLayerPolygons = new ol.layer.Vector({
source: vectorSourcePolygons,
style: [
new ol.style.Style({
stroke: new ol.style.Stroke({
color: [0, 121, 88, 1],
width: 2
})
})
]
});
// Declare a vector layer for bboxPolygon
var vectorLayerBboxPolygon = new ol.layer.Vector({
source: new ol.source.Vector(),
style: [
new ol.style.Style({
stroke: new ol.style.Stroke({
color: [0, 0, 0, 1],
width: 2
})
})
]
});
// Instanciate a map and add layers
var map = new ol.Map({
target: 'map',
layers: [
new ol.layer.Tile({
source: new ol.source.OSM()
}),
vectorLayerPolygons,
vectorLayerBboxPolygon
],
view: new ol.View({
center: ol.proj.transform(
[-1.5603, 47.2383],
'EPSG:4326',
'EPSG:3857'
),
zoom: 11
})
});
fetch('assets/data/quartiers_nantes.geojson').then(function(response) {
return response.json().then(function(polys_fc) {
console.log(polys_fc);
vectorSourcePolygons.addFeatures(geojsonToFeatures(polys_fc, {
featureProjection: 'EPSG:3857'
}));
// Create a button and bind a click function
var button = document.getElementById('createbboxpolygon');
var draw;
button.addEventListener('click', function(e) {
var source = vectorLayerBboxPolygon.getSource();
source.clear();
// Random feature extraction
var features = vectorLayerPolygons.getSource().getFeatures();
var feat = features[getRandomInt(0, features.length - 1)];
// Get extent
var featureExtent = ol.proj.transformExtent(feat.getGeometry().getExtent(), 'EPSG:3857', 'EPSG:4326');
// Create a GeoJSON reusing the extent
var featureBboxPolygon = turf.bboxPolygon(featureExtent);
source.addFeatures(geojsonToFeatures(featureBboxPolygon, {
featureProjection: 'EPSG:3857'
}));
});
});
});
</script>
</body>
</html>