Display a pop-up | OpenLayers

Learn how to display feature attributes in a pop-up.

Display a popup using API key authentication

A pop-up, also known as a "popup", is a visual element that displays information about a feature when it is clicked. You typically style and configure a pop-up using HTML and CSS for each layer in a map. Pop-ups can display attribute values, calculated values, or rich content such as images, charts, or videos.

In this tutorial, you create an interactive pop-up for the Trailheads feature layer in the Santa Monica Mountains. When a feature is clicked, a pop-up is displayed containing the name of the trail and the service that manages it. You use the ol-popup library to achieve this.

Prerequisites

You need an ArcGIS Location Platform or ArcGIS Online account.

Steps

Get the starter app

Select a type of authentication and follow the steps to create a new app.

Choose API key authentication if you:

Want the easiest way to get started.
Want to build public applications that access ArcGIS Location Services and secure items.
Have an ArcGIS Location Platform or ArcGIS Online account.

Choose user authentication if you:

Want to build private applications.
Require application users to sign in with their own ArcGIS account and access resources their behalf.
Have an ArcGIS Online account.

To learn more about both types of authentication, go to Authentication.

You can choose one of the following to create a new CodePen:

Option 1: Complete the Display a map tutorial; or,
Option 2: Start from the Display a map tutorial .

Set up authentication

Create a new API key credential with the correct privileges to get an access token.

Go to the Create an API key tutorial and create an API key with the following privilege(s):
- Privileges
  - Location services > Basemaps
- Item access
  - Note: If you are using your own custom data layer for this tutorial, you need to grant the API key credentials access to the layer item. Learn more in Item access privileges.

Set developer credentials

Use the API key or OAuth developer credentials so your application can access ArcGIS services.

Update the accessToken variable to use your API key.

Expand
Use dark colors for code blocks
    /* Use for API key authentication */
    const accessToken = "YOUR_ACCESS_TOKEN";
Expand

In both the index.html and callback.html files, replace YOUR_CLIENT_ID and YOUR_REDIRECT_URL with the client ID and redirect URL of your OAuth credentials.

index.html
Use dark colors for code blocks
    /* Use for user authentication */
    const clientId = "YOUR_CLIENT_ID"; // Your client ID from OAuth credentials
    const redirectUri = ""YOUR_REDIRECT_URI""; // The redirect URL registered in your OAuth credentials
    const session = await arcgisRest.ArcGISIdentityManager.beginOAuth2({
      clientId,
      redirectUri,
      portal: "https://www.arcgis.com/sharing/rest" // Your portal URL
    });

    const accessToken = session.token;

callback.html
Use dark colors for code blocks
    arcgisRest.ArcGISIdentityManager.completeOAuth2({
      clientId: "YOUR_CLIENT_ID", // Your client ID from OAuth credentials
      redirectUri: "YOUR_REDIRECT_URI", // The redirect URL registered in your OAuth credentials
      portal: "https://www.arcgis.com/sharing/rest" // Your portal URL
    });

Run the app and ensure you can sign in successfully.

If you are unable to sign in, make sure you have the correct redirect URL and port. This URL varies based on your application and typically takes the format of https://<server>[:port]/callback.html or http://my-arcgis-app:/auth. For example, if you are running an application on http://127.0.0.1:5500/, set http://127.0.0.1:5500/callback.html as your redirect URL in the index.html and callback.html file and your developer credential. They all have to match!

Add the pop-up library

OpenLayers does not include a pop-up component. You can use the third-party library ol-popup to simplify adding pop-ups to your map.

In the <head> element, add references to the ol-popup library.

Expand
Use dark colors for code blocks
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@v10.6.0/ol.css">
    <script src="https://cdn.jsdelivr.net/npm/ol@v10.6.0/dist/ol.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/ol-mapbox-style@13.1.0/dist/olms.js"></script>

    <script src="https://unpkg.com/ol-popup@5.1.1/dist/ol-popup.js"></script>
    <link rel="stylesheet" href="https://unpkg.com/ol-popup@5.1.1/src/ol-popup.css">
Expand

Add the trailheads layer

Use a Vector layer with a Vector source to display the trailheads as GeoJSON.

For more information about adding feature layers using GeoJSON, see the Add a feature layer as GeoJSON tutorial.

Before the olms initialization, create a a Vector layer. Give it a Vector source with a GeoJSON feature format to load and display the trailheads feature layer. Save it to a trailheadsLayer variable.

Expand
Use dark colors for code blocks
    const basemapId = "arcgis/outdoor";

    const trailheadsLayer = new ol.layer.Vector({
      source: new ol.source.Vector({
        format: new ol.format.GeoJSON(),
        url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0/query?where=1%3D1&outFields=*&returnGeometry=true&f=pgeojson",

      })
    });
Expand

Add the data attribution for the vector tile layer source.

Go to the Trailheads (Santa Monica Mountains) item.
Scroll down to the Acknowledgments section and copy its value.

Paste the copied value to the attributions property.

Expand
Use dark colors for code blocks
    const basemapId = "arcgis/outdoor";

    const trailheadsLayer = new ol.layer.Vector({
      source: new ol.source.Vector({
        format: new ol.format.GeoJSON(),
        url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0/query?where=1%3D1&outFields=*&returnGeometry=true&f=pgeojson",

        // Attribution text retrieved from https://arcgis.com/home/item.html?id=883cedb8c9fe4524b64d47666ed234a7
        attributions: ["| Los Angeles GeoHub"]

      })
    });
Expand

Inside olms load handler, use map.addLayer to add this layer to the map.

Expand
Use dark colors for code blocks
    olms.apply(map, `https://basemapstyles-api.arcgis.com/arcgis/rest/services/styles/v2/styles/${basemapId}?token=${accessToken}`).then(function (map) {

      map.addLayer(trailheadsLayer);

      // Add Esri attribution
      // Learn more in https://esriurl.com/attribution
      const source = map.getLayers().item(0).getSource();
      const poweredByEsriString = "Powered by <a href='https://www.esri.com/en-us/home' target='_blank'>Esri</a> | ";

      const attributionFn = source.getAttributions();
      if (attributionFn) {
        source.setAttributions((ViewStateLayerStateExtent) => {
          return [poweredByEsriString, ...attributionFn(ViewStateLayerStateExtent)];
        });
      } else source.setAttributions(poweredByEsriString);
    });
Expand

Initialize the pop-up

A Popup is a type of Overlay. Use map.addOverlay to add it to the map.

Create a new Popup and save it to a popup variable. Add it to the map with map.addOverlay.

Expand
Use dark colors for code blocks
      map.addLayer(trailheadsLayer);

      // Add Esri attribution
      // Learn more in https://esriurl.com/attribution
      const source = map.getLayers().item(0).getSource();
      const poweredByEsriString = "Powered by <a href='https://www.esri.com/en-us/home' target='_blank'>Esri</a> | ";

      const attributionFn = source.getAttributions();
      if (attributionFn) {
        source.setAttributions((ViewStateLayerStateExtent) => {
          return [poweredByEsriString, ...attributionFn(ViewStateLayerStateExtent)];
        });
      } else source.setAttributions(poweredByEsriString);
    });

    const popup = new Popup();
    map.addOverlay(popup);
Expand

Display a pop-up on click

A pop-up can display any HTML content. Use a click event handler to detect the click, then use map.getFeaturesAtPixel to find any trailhead features at the clicked point. You pass a function as a layerFilter to do so.

If the returned array contains at least one feature, you can use Feature.get to extract the trail name (TRL_NAME) and park name (PARK_NAME). You then use popup.show to update the pop-up position and content.

Add a click event handler. Inside, use getFeaturesAtPixel to get an array of trailhead features clicked on.

Expand
Use dark colors for code blocks
    const popup = new Popup();
    map.addOverlay(popup);

    map.on("click", (event) => {

      const trailheads = map.getFeaturesAtPixel(event.pixel, {
        layerFilter: (layer) => layer === trailheadsLayer
      });

    });
Expand

If there is a trail name to show, use popup.show to set the position and content of the pop-up. Otherwise, use popup.hide to hide it.

Expand
Use dark colors for code blocks
      const trailheads = map.getFeaturesAtPixel(event.pixel, {
        layerFilter: (layer) => layer === trailheadsLayer
      });

      if (trailheads.length > 0) {

        const trailName = trailheads[0].get("TRL_NAME");
        const parkName = trailheads[0].get("PARK_NAME");
        popup.show(event.coordinate, `<b>${trailName}</b></br>${parkName}`);

      } else {
        popup.hide();
      }
Expand

Run the app

Run the app.

The map view should display the Trailheads feature layer. When you click a feature, the name of the trailhead and its park name is displayed in a pop-up.