containsLocation()

This example draws a red circle when the clicked point falls outside of the specified polygon (the Bermuda Triangle), and a blue triangle when the click falls inside the polygon.

Read the documentation.

TypeScriptJavaScriptCSSHTML 
// This example requires the Geometry library. Include the libraries=geometry
// parameter when you first load the API. For example:
// <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry">

function initMap(): void {
  const map = new google.maps.Map(
    document.getElementById("map") as HTMLElement,
    {
      center: { lat: 24.886, lng: -70.269 },
      zoom: 5,
    }
  );

  const triangleCoords = [
    { lat: 25.774, lng: -80.19 },
    { lat: 18.466, lng: -66.118 },
    { lat: 32.321, lng: -64.757 },
  ];

  const bermudaTriangle = new google.maps.Polygon({ paths: triangleCoords });

  google.maps.event.addListener(map, "click", (e) => {
    const resultColor = google.maps.geometry.poly.containsLocation(
      e.latLng,
      bermudaTriangle
    )
      ? "blue"
      : "red";

    const resultPath = google.maps.geometry.poly.containsLocation(
      e.latLng,
      bermudaTriangle
    )
      ? // A triangle.
        "m 0 -1 l 1 2 -2 0 z"
      : google.maps.SymbolPath.CIRCLE;

    new google.maps.Marker({
      position: e.latLng,
      map,
      icon: {
        path: resultPath,
        fillColor: resultColor,
        fillOpacity: 0.2,
        strokeColor: "white",
        strokeWeight: 0.5,
        scale: 10,
      },
    });
  });
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;
index.ts
 
// This example requires the Geometry library. Include the libraries=geometry
// parameter when you first load the API. For example:
// <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry">
function initMap() {
  const map = new google.maps.Map(document.getElementById("map"), {
    center: { lat: 24.886, lng: -70.269 },
    zoom: 5,
  });
  const triangleCoords = [
    { lat: 25.774, lng: -80.19 },
    { lat: 18.466, lng: -66.118 },
    { lat: 32.321, lng: -64.757 },
  ];
  const bermudaTriangle = new google.maps.Polygon({ paths: triangleCoords });

  google.maps.event.addListener(map, "click", (e) => {
    const resultColor = google.maps.geometry.poly.containsLocation(
      e.latLng,
      bermudaTriangle,
    )
      ? "blue"
      : "red";
    const resultPath = google.maps.geometry.poly.containsLocation(
      e.latLng,
      bermudaTriangle,
    )
      ? // A triangle.
        "m 0 -1 l 1 2 -2 0 z"
      : google.maps.SymbolPath.CIRCLE;

    new google.maps.Marker({
      position: e.latLng,
      map,
      icon: {
        path: resultPath,
        fillColor: resultColor,
        fillOpacity: 0.2,
        strokeColor: "white",
        strokeWeight: 0.5,
        scale: 10,
      },
    });
  });
}

window.initMap = initMap;
index.js
 
/* 
 * 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;
}

style.css
 
<html>
  <head>
    <title>Polygon Contains Location</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&libraries=geometry&v=weekly"
      defer
    ></script>
  </body>
</html>
index.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-poly-containsLocation 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