Data Layer: Event Handling

This example uses a data layer to dynamically display information about a KML feature object when under the mouse cursor.

Read the documentation.

TypeScript

let map: google.maps.Map;

function initMap(): void {
  map = new google.maps.Map(document.getElementById("map") as HTMLElement, {
    zoom: 4,
    center: { lat: -28, lng: 137 },
  });

  // Load GeoJSON.
  map.data.loadGeoJson(
    "https://storage.googleapis.com/maps-devrel/google.json"
  );

  // Add some style.
  map.data.setStyle((feature) => {
    return /** @type {google.maps.Data.StyleOptions} */ {
      fillColor: feature.getProperty("color"),
      strokeWeight: 1,
    };
  });

  // Set mouseover event for each feature.
  map.data.addListener("mouseover", (event) => {
    (document.getElementById("info-box") as HTMLElement).textContent =
      event.feature.getProperty("letter");
  });
}

JavaScript

let map;

function initMap() {
  map = new google.maps.Map(document.getElementById("map"), {
    zoom: 4,
    center: { lat: -28, lng: 137 },
  });
  // Load GeoJSON.
  map.data.loadGeoJson(
    "https://storage.googleapis.com/maps-devrel/google.json"
  );
  // Add some style.
  map.data.setStyle((feature) => {
    return /** @type {google.maps.Data.StyleOptions} */ {
      fillColor: feature.getProperty("color"),
      strokeWeight: 1,
    };
  });
  // Set mouseover event for each feature.
  map.data.addListener("mouseover", (event) => {
    document.getElementById("info-box").textContent =
      event.feature.getProperty("letter");
  });
}

CSS

/* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
#map {
  height: 100%;
}

/* Optional: Makes the sample page fill the window. */
html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#info-box {
  background-color: white;
  border: 1px solid black;
  bottom: 30px;
  height: 20px;
  padding: 10px;
  position: absolute;
  left: 30px;
}

HTML

<!DOCTYPE html>
<html>
  <head>
    <title>Data Layer: Event Handling</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script src="./index.js"></script>
  </head>
  <body>
    <div id="map"></div>
    <div id="info-box">?</div>

    <!-- Async script executes immediately and must be after any DOM elements used in callback. -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap&libraries=&v=weekly"
      async
    ></script>
  </body>
</html>
let map; function initMap() { map = new google.maps.Map(document.getElementById("map"), { zoom: 4, center: { lat: -28, lng: 137 }, }); // Load GeoJSON. map.data.loadGeoJson( "https://storage.googleapis.com/maps-devrel/google.json" ); // Add some style. map.data.setStyle((feature) => { return /** @type {google.maps.Data.StyleOptions} */ { fillColor: feature.getProperty("color"), strokeWeight: 1, }; }); // Set mouseover event for each feature. map.data.addListener("mouseover", (event) => { document.getElementById("info-box").textContent = event.feature.getProperty("letter"); }); }
/* Always set the map height explicitly to define the size of the div * element that contains the map. */ #map { height: 100%; } /* Optional: Makes the sample page fill the window. */ html, body { height: 100%; margin: 0; padding: 0; } #info-box { background-color: white; border: 1px solid black; bottom: 30px; height: 20px; padding: 10px; position: absolute; left: 30px; }
<!DOCTYPE html> <html> <head> <title>Data Layer: Event Handling</title> <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script> <!-- jsFiddle will insert css and js --> </head> <body> <div id="map"></div> <div id="info-box">?</div> <!-- Async script executes immediately and must be after any DOM elements used in callback. --> <script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&libraries=&v=weekly" async ></script> </body> </html>

Try Sample

Clone Sample

Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.

  git clone -b sample-layer-data-event git@github.com:googlemaps/js-samples.git
  cd js-samples
  npm i
  npm start

Other samples can be tried by switching to any branch beginning with sample-SAMPLE_NAME.

  git checkout sample-SAMPLE_NAME
  npm i
  npm start