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>

All

<!DOCTYPE html>
<html>
  <head>
    <title>Data Layer: Event Handling</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <style type="text/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;
      }
    </style>
    <script>
      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");
        });
      }
    </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>