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<head>
<title>Add TopoJSON data to the map - Azure Maps Web SDK Samples</title>
<meta charset="utf-8" />
<link rel="shortcut icon" href="/favicon.ico"/>
<meta http-equiv="x-ua-compatible" content="IE=Edge" />
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
<meta name="description" content="This sample shows how to add TopoJSON data to the map, by converting it into GeoJSON in a Web Worker so that map can easily render it." />
<meta name="keywords" content="Microsoft maps, map, gis, API, SDK, TopoJSON" />
<meta name="author" content="Microsoft Azure Maps" />
<!-- Add references to the Azure Maps Map control JavaScript and CSS files. -->
<link rel="stylesheet" href="https://atlas.microsoft.com/sdk/javascript/mapcontrol/2/atlas.min.css" type="text/css" />
<script src="https://atlas.microsoft.com/sdk/javascript/mapcontrol/2/atlas.min.js"></script>
<!-- Load in Catiline.js library which makes it easier to work with web workers. -->
<script src="../Common/scripts/catiline.min.js"></script>
<script type='text/javascript'>
var map, datasource, popup, topojsonWorker;
function GetMap() {
//Point the Azure Maps domain to the US Azure Gov Cloud domain.
atlas.setDomain('atlas.azure.us');
//Initialize a map instance.
map = new atlas.Map('myMap', {
style: 'grayscale_dark',
view: 'Auto',
//Add authentication details for connecting to Azure Maps.
authOptions: {
//Use Azure Active Directory authentication.
authType: 'anonymous',
clientId: 'c9f2f391-13f1-407b-a4a5-f0a241bacfbf', //Your Azure Active Directory client id for accessing your Azure Maps account.
getToken: function (resolve, reject, map) {
//URL to your authentication service that retrieves an Azure Active Directory Token.
var tokenServiceUrl = 'https://azuremapscodesamples.azurewebsites.us/Common/TokenService.ashx';
fetch(tokenServiceUrl).then(r => r.text()).then(token => resolve(token));
}
//Alternatively, use an Azure Maps key. Get an Azure Maps key at https://azure.com/maps. NOTE: The primary key should be used as the key.
//authType: 'subscriptionKey',
//subscriptionKey: '<Your Azure Maps Key>'
}
});
//Wait until the map resources are ready.
map.events.add('ready', function () {
popup = new atlas.Popup();
//Create a data source to add your data to.
datasource = new atlas.source.DataSource();
map.sources.add(datasource);
//Add a layer for the polygon areas and add it below the map labels.
var polygonLayer = new atlas.layer.PolygonLayer(datasource);
map.layers.add(polygonLayer, 'labels');
//Add a line layer for the polygon outlines.
map.layers.add(new atlas.layer.LineLayer(datasource, null, {
strokeColor: 'white'
}));
map.events.add('click', polygonLayer, featureClicked);
//Create a web worker that uses the topojson-client library.
var wfunc = function (base, cb) {
//Import the topojson-client library.
importScripts('https://unpkg.com/topojson-client@3');
//Download the topojson data.
fetch(base)
.then(response => response.json())
.then(function (topology) {
//Extract all layers from the TopoJSON topology and convert into GeoJSON.
var geojson = [];
Object.keys(topology.objects).forEach(function (val, idx, arr) {
var d = topojson.feature(topology, topology.objects[val]);
if (d.type === 'FeatureCollection') {
geojson = geojson.concat(d.features);
} else {
geojson.push(d);
}
});
cb(geojson);
});
};
topojsonWorker = cw({ data: wfunc }, 2);
});
}
function loadTopoJsonFile(url) {
datasource.clear();
popup.close();
document.getElementById('loadingIcon').style.display = '';
topojsonWorker.data(cw.makeUrl(url)).then(function (geojson) {
//Add the GeoJSON to the map.
datasource.add(geojson);
//Set the map view over the data.
map.setCamera({
bounds: atlas.data.BoundingBox.fromData(geojson)
});
document.getElementById('loadingIcon').style.display = 'none';
});
}
function featureClicked(e) {
//Make sure the event occurred on a shape feature.
if (e.shapes && e.shapes.length > 0) {
//By default, show the popup where the mouse event occurred.
var pos = e.position;
var offset = [0, 0];
var properties;
if (e.shapes[0] instanceof atlas.Shape) {
properties = e.shapes[0].getProperties();
//If the shape is a point feature, show the popup at the points coordinate.
if (e.shapes[0].getType() === 'Point') {
pos = e.shapes[0].getCoordinates();
offset = [0, -18];
}
} else {
properties = e.shapes[0].properties;
//If the shape is a point feature, show the popup at the points coordinate.
if (e.shapes[0].type === 'Point') {
pos = e.shapes[0].geometry.coordinates;
offset = [0, -18];
}
}
//Update the content and position of the popup.
popup.setOptions({
//Create a table from the properties in the feature.
content: atlas.PopupTemplate.applyTemplate(properties),
position: pos,
pixelOffset: offset
});
//Open the popup.
popup.open(map);
}
}
</script>
</head>
<body onload="GetMap()">
<div id="myMap" style="position:relative;width:100%;min-width:290px;height:600px;"></div>
<div style="position:absolute;top:10px;left:10px;background-color:white;border-radius:5px;padding:5px;">
Load TopoJSON:<br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/Spain_Municipalities.json')" value="Spain Municipalities (1.5MB)" /><br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/Brazil_Municipalities.json')" value="Brazil Municipalities (3.5MB)" /><br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/zips_us_topo.json')" value="US Zip Codes (5.3MB)" /><br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/neilsen_dma.json')" value="Neilsen DMA (700KB)" /><br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/sandiego_zoning_datasd.topojson')" value="San Diego Zoning data (7.3MB)" /><br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/England_Electoral_Wards.json')" value="England Electoral Wards (4.3MB)" /><br />
<input type="button" onclick="loadTopoJsonFile('../Common/data/topojson/zip-code-level-2017-topojson.json')" value="US Zip Code Tabulation Areas 2018 (35MB)" />
</div>
<img id="loadingIcon" src="../Common/images/loadingIcon.gif" title="Loading" style="position:absolute;left:calc(50% - 25px);top:250px;display:none;" />
<fieldset style="width:calc(100% - 30px);min-width:290px;margin-top:10px;">
<legend><h1 style="font-size:16px">Add TopoJSON data to the map</h1></legend>
This sample shows how to add TopoJSON data to the map, by converting it into GeoJSON in a Web Worker so that map can easily render it.
TopoJSON data is an extension of GeoJSON that encodes topology.
This is ideal for reducing the file size of polygon data sets that that share edges.
This sample uses the open source <a href="https://github.com/topojson/topojson-client">topojson-client library</a> for converting the decoding the TopoJSON data into GeoJSON which can be easily add to the map.
It also makes use of the open source <a href="http://catilinejs.com/">Catiline.js</a> library which makes working with web workers easier.
<br />
<br />
<b>Note:</b> Not all file and mime types are enabled in all servers. If using .NET, it is recommended to add the following to the web.config file:
<br />
<br />
&lt;system.webServer&gt;<br />&nbsp;&nbsp;&lt;staticContent&gt;<br />&nbsp;&nbsp;&nbsp;&nbsp;&lt;mimeMap fileExtension=&quot;.topojson&quot; mimeType=&quot;application/json&quot; /&gt;<br />&nbsp;&nbsp;&lt;/staticContent&gt;<br />&lt;system.webServer&gt;
</fieldset>
</body>
</html>