Display a pop-up

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

An ArcGIS Location Platform or ArcGIS Online account.

Steps

Get the starter app

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

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 developer credentials in your portal for the type of authentication you selected.

Create a new API key credential with the correct privileges to access the resources used in this tutorial.

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.
Copy the API key access token to your clipboard when prompted.

Set developer credentials

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

Update the accessToken variable to use your API key.

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    /* Use for API key authentication */
    const accessToken = "YOUR_ACCESS_TOKEN";
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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
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    /* 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
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    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.

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  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@v10.5.0/ol.css" type="text/css" />
  <script src="https://cdn.jsdelivr.net/npm/ol@v10.5.0/dist/ol.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/ol-mapbox-style@12.5.0/dist/olms.js" type="text/javascript"></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" />
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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.

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    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`,

      })
    });
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Add the data attribution for the vector tile layer source.

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

Create an attribution property and paste the attribution value from the item.

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    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']

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

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    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);
    });
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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.

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      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);
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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.

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

    map.on("click", (event) => {
      let trailName, parkName;

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

    });
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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.

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      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();
      }
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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.

What's next?

Learn how to use additional ArcGIS location services in these tutorials:

Query a feature layer (spatial)

Execute a spatial query to access polygon features from a feature service.

Get global data

Query demographic information for locations around the world with the GeoEnrichment service.

Get local data

Query regional facts, spending trends, and psychographics with the GeoEnrichment service.

Add a feature layer

Add features from feature layers to a map.