Feature Collection Parsing
Parse a feature collection contained in a webmap to GeoJSON.
<html>
<head>
<meta charset="utf-8" />
<title>Feature Collection Parsing</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<!-- Load Leaflet from CDN -->
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.5.1/dist/leaflet.css"
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<script src="https://unpkg.com/leaflet@1.5.1/dist/leaflet.js"
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<script src="https://unpkg.com/esri-leaflet@2.3.0/dist/esri-leaflet.js"
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<style>
body { margin:0; padding:0; }
#map { position: absolute; top:0; bottom:0; right:0; left:0; }
</style>
</head>
<body>
<div id="map"></div>
<script>
var map = L.map('map');
L.esri.basemapLayer('Topographic').addTo(map);
L.esri.get('https://www.arcgis.com/sharing/content/items/62914b2820c24d4e95710ebae77937cb/data', {}, function (error, response) {
if (error) {
return;
}
var features = response.operationalLayers[0].featureCollection.layers[0].featureSet.features;
var idField = response.operationalLayers[0].featureCollection.layers[0].layerDefinition.objectIdField;
// empty geojson feature collection
var featureCollection = {
type: 'FeatureCollection',
features: []
};
for (var i = features.length - 1; i >= 0; i--) {
// convert ArcGIS Feature to GeoJSON Feature
var feature = L.esri.Util.arcgisToGeoJSON(features[i], idField);
// unproject the web mercator coordinates to lat/lng
var latlng = L.Projection.Mercator.unproject(L.point(feature.geometry.coordinates));
feature.geometry.coordinates = [latlng.lng, latlng.lat];
featureCollection.features.push(feature);
}
var geojson = L.geoJSON(featureCollection).addTo(map);
map.fitBounds(geojson.getBounds());
});
</script>
</body>
</html>