Marker Collision Management

Handle marker collisions

Collision behavior controls how a marker will display if it collides (overlaps) with another marker. Collision behavior is only supported when using Advanced Markers on a vector map.

To set collision behavior, set AdvancedMarkerView.collisionBehavior to one of the following:

  • REQUIRED: (default) Always display the marker regardless of collision.
  • OPTIONAL_AND_HIDES_LOWER_PRIORITY Display the marker only if it does not overlap with other markers. If two markers of this type would overlap, the one with the higher zIndex is shown. If they have the same zIndex, the one with the lower vertical screen position is shown.
  • REQUIRED_AND_HIDES_OPTIONAL Always display the marker regardless of collision, and hide any OPTIONAL_AND_HIDES_LOWER_PRIORITY markers or labels that would overlap with the marker.

The following example always displays markers and hides underlying labels:

const advancedMarker = new google.maps.marker.AdvancedMarkerView({
  position: new google.maps.LatLng({ lat, lng }),
  map,
  collisionBehavior: google.maps.CollisionBehavior.REQUIRED_AND_HIDES_OPTIONAL,
});

The following example hides markers if they collide with a required marker and hides underlying labels:

const advancedMarker = new google.maps.marker.AdvancedMarkerView({
  position: new google.maps.LatLng({ lat, lng }),
  map,
  collisionBehavior: google.maps.CollisionBehavior.OPTIONAL_AND_HIDES_LOWER_PRIORITY,
});

TypeScript

let map: google.maps.Map;

// Initialize and add the map
function initMap(): void {
  let markers: google.maps.marker.AdvancedMarkerView[] = [];

  let collisionBehavior = google.maps.CollisionBehavior.REQUIRED;

  map = new google.maps.Map(
    document.getElementById("map") as HTMLElement,
    {
      mapId: "6ff586e93e18149f",
      center: { lat: 47.609414458375674, lng: -122.33897030353548 },
      zoom: 17,
    } as google.maps.MapOptions
  );

  const menuList = document.querySelector(".mdc-list") as HTMLUListElement;

  // Add the behaviors to the select options
  for (const [key, value] of Object.entries(google.maps.CollisionBehavior)) {
    const item = document.createElement("LI");

    item.classList.add("mdc-list-item");
    item.setAttribute("data-value", key);

    const itemText = document.createElement("SPAN") as HTMLSpanElement;

    itemText.classList.add("mdc-list-item__text");
    itemText.innerText = value as string;

    item.appendChild(itemText);
    menuList.appendChild(item);
  }

  // @ts-ignore
  const select = new mdc.select.MDCSelect(
    document.querySelector(".mdc-select") as HTMLElement
  );


  select.listen("MDCSelect:change", () => {
    collisionBehavior = select.value;
    markers.forEach((marker) => {
      marker.collisionBehavior = collisionBehavior;
    });
  });

  select.value = collisionBehavior;

  // Create some markers on the map
  let locations = [
    [-122.3402, 47.6093],
    [-122.3402, 47.6094],
    [-122.3403, 47.6094],
    [-122.3384, 47.6098],
    [-122.3389, 47.6095],
    [-122.3396, 47.6095],
    [-122.3379, 47.6097],
    [-122.3378, 47.6097],
    [-122.3396, 47.6091],
    [-122.3383, 47.6089],
    [-122.3379, 47.6093],
    [-122.3381, 47.6095],
    [-122.3378, 47.6095],
  ];

  locations.forEach(([lng, lat]: number[]) => {
    const advancedMarker = new google.maps.marker.AdvancedMarkerView({
      position: new google.maps.LatLng({ lat, lng }),
      map,
      collisionBehavior: collisionBehavior,
    });
    markers.push(advancedMarker);
  });
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;

JavaScript

let map;

// Initialize and add the map
function initMap() {
  let markers = [];
  let collisionBehavior = google.maps.CollisionBehavior.REQUIRED;

  map = new google.maps.Map(document.getElementById("map"), {
    mapId: "6ff586e93e18149f",
    center: { lat: 47.609414458375674, lng: -122.33897030353548 },
    zoom: 17,
  });

  const menuList = document.querySelector(".mdc-list");

  // Add the behaviors to the select options
  for (const [key, value] of Object.entries(google.maps.CollisionBehavior)) {
    const item = document.createElement("LI");

    item.classList.add("mdc-list-item");
    item.setAttribute("data-value", key);

    const itemText = document.createElement("SPAN");

    itemText.classList.add("mdc-list-item__text");
    itemText.innerText = value;
    item.appendChild(itemText);
    menuList.appendChild(item);
  }

  // @ts-ignore
  const select = new mdc.select.MDCSelect(
    document.querySelector(".mdc-select")
  );

  select.listen("MDCSelect:change", () => {
    collisionBehavior = select.value;
    markers.forEach((marker) => {
      marker.collisionBehavior = collisionBehavior;
    });
  });
  select.value = collisionBehavior;

  // Create some markers on the map
  let locations = [
    [-122.3402, 47.6093],
    [-122.3402, 47.6094],
    [-122.3403, 47.6094],
    [-122.3384, 47.6098],
    [-122.3389, 47.6095],
    [-122.3396, 47.6095],
    [-122.3379, 47.6097],
    [-122.3378, 47.6097],
    [-122.3396, 47.6091],
    [-122.3383, 47.6089],
    [-122.3379, 47.6093],
    [-122.3381, 47.6095],
    [-122.3378, 47.6095],
  ];

  locations.forEach(([lng, lat]) => {
    const advancedMarker = new google.maps.marker.AdvancedMarkerView({
      position: new google.maps.LatLng({ lat, lng }),
      map,
      collisionBehavior: collisionBehavior,
    });

    markers.push(advancedMarker);
  });
}

window.initMap = initMap;

CSS

:root {
  --mdc-theme-primary: #1a73e8;
  --mdc-theme-secondary: #rgb(225, 245, 254);
  --mdc-theme-on-primary: #fff;
  --mdc-theme-on-secondary: rgb(1, 87, 155);
}

.mdc-text-field--focused:not(.mdc-text-field--disabled) .mdc-floating-label {
  color: var(--mdc-theme-primary);
}

.mdc-select--focused .mdc-select__dropdown-icon {
  background: url(data:image/svg+xml,%3Csvg%20width%3D%2210px%22%20height%3D%225px%22%20viewBox%3D%227%2010%2010%205%22%20version%3D%221.1%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22%3E%0A%20%20%20%20%3Cpolygon%20id%3D%22Shape%22%20stroke%3D%22none%22%20fill%3D%22%23000%22%20fill-rule%3D%22evenodd%22%20opacity%3D%220.54%22%20points%3D%227%2010%2012%2015%2017%2010%22%3E%3C%2Fpolygon%3E%0A%3C%2Fsvg%3E) no-repeat center;
}

.mdc-select:not(.mdc-select--disabled).mdc-select--focused .mdc-floating-label {
  color: var(--mdc-theme-primary);
}

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

#container {
  height: 100%;
  display: flex;
}

#sidebar {
  flex-basis: 15rem;
  flex-grow: 1;
  padding: 1rem;
  max-width: 30rem;
  height: 100%;
  box-sizing: border-box;
  overflow: auto;
}

#map {
  flex-basis: 0;
  flex-grow: 4;
  height: 100%;
}

.mdc-select,
.mdc-select__anchor,
.mdc-select__menu {
  width: 100%;
}

[class$=api-load-alpha-banner] {
  display: none;
}

HTML

<html>
  <head>
    <title>Advanced Marker Collision Management</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <link
      href="https://unpkg.com/material-components-web@6.0.0/dist/material-components-web.css"
      rel="stylesheet"
    />
    <script src="https://unpkg.com/material-components-web@6.0.0/dist/material-components-web.min.js"></script>
    <link
      rel="stylesheet"
      href="https://fonts.googleapis.com/icon?family=Material+Icons"
    />

    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script type="module" src="./index.js"></script>
  </head>
  <body>
    <div id="container">
      <div id="map"></div>
      <div id="sidebar">
        <div class="mdc-select mdc-select--outlined">
          <div
            class="mdc-select__anchor"
            aria-labelledby="outlined-select-label"
          >
            <input
              type="text"
              disabled
              readonly
              id="demo-selected-text"
              class="mdc-select__selected-text"
            />
            <i class="mdc-select__dropdown-icon"></i>
            <span class="mdc-notched-outline">
              <span class="mdc-notched-outline__leading"></span>
              <span class="mdc-notched-outline__notch">
                <span
                  id="outlined-select-label"
                  class="mdc-floating-label mdc-theme--primary"
                  >Pick a Collision Behavior</span
                >
              </span>
              <span class="mdc-notched-outline__trailing"></span>
            </span>
          </div>
          <div class="mdc-select__menu mdc-menu mdc-menu-surface">
            <ul class="mdc-list"></ul>
          </div>
        </div>
      </div>
    </div>

    <!-- 
      The `defer` attribute causes the callback 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=marker&v=beta"
      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-advanced-markers-collision 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