This example uses a data layer to dynamically change the appearance of some KML feature objects when the user hovers over or clicks them.
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/mapsdevsite/json/google.json" ); // Color each letter gray. Change the color when the isColorful property // is set to true. map.data.setStyle((feature) => { let color = "gray"; if (feature.getProperty("isColorful")) { color = feature.getProperty("color") as string; } return /** @type {!google.maps.Data.StyleOptions} */ { fillColor: color, strokeColor: color, strokeWeight: 2, }; }); // When the user clicks, set 'isColorful', changing the color of the letters. map.data.addListener("click", (event) => { event.feature.setProperty("isColorful", true); }); // When the user hovers, tempt them to click by outlining the letters. // Call revertStyle() to remove all overrides. This will use the style rules // defined in the function passed to setStyle() map.data.addListener("mouseover", (event) => { map.data.revertStyle(); map.data.overrideStyle(event.feature, { strokeWeight: 8 }); }); map.data.addListener("mouseout", (event) => { map.data.revertStyle(); }); } declare global { interface Window { initMap: () => void; } } window.initMap = initMap;
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/mapsdevsite/json/google.json", ); // Color each letter gray. Change the color when the isColorful property // is set to true. map.data.setStyle((feature) => { let color = "gray"; if (feature.getProperty("isColorful")) { color = feature.getProperty("color"); } return /** @type {!google.maps.Data.StyleOptions} */ { fillColor: color, strokeColor: color, strokeWeight: 2, }; }); // When the user clicks, set 'isColorful', changing the color of the letters. map.data.addListener("click", (event) => { event.feature.setProperty("isColorful", true); }); // When the user hovers, tempt them to click by outlining the letters. // Call revertStyle() to remove all overrides. This will use the style rules // defined in the function passed to setStyle() map.data.addListener("mouseover", (event) => { map.data.revertStyle(); map.data.overrideStyle(event.feature, { strokeWeight: 8 }); }); map.data.addListener("mouseout", (event) => { map.data.revertStyle(); }); } window.initMap = initMap;
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; }
HTML
<html> <head> <title>Data Layer: Dynamic Styling</title> <link rel="stylesheet" type="text/css" href="./style.css" /> <script type="module" src="./index.js"></script> </head> <body> <div id="map"></div> <!-- The `defer` attribute causes the script to execute after the full HTML document has been parsed. For non-blocking uses, avoiding race conditions, and consistent behavior across browsers, consider loading using Promises. See https://developers.google.com/maps/documentation/javascript/load-maps-js-api for more information. --> <script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly" defer ></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-dynamic https://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