Display a pop-up | OpenLayers

Learn how to display featureA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more attributes in a pop-upA pop-up is a visual element used to display data for features or graphics in a map.Learn more.

Display a popup using API key authentication

A pop-upA pop-up is a visual element used to display data for features or graphics in a map.Learn more, also known as a "popup", is a visual element that displays information about a featureA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more when it is clicked. You typically style and configure a pop-up using HTML and CSS for each layerA layer is a reference to a collection of geographic data that is used to access and display data. The data for layers are typically provided by the basemap layer service and data services.Learn more 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 layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more in the Santa Monica Mountains. When a featureA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more 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 applicationsA public application is an application that allows anonymous access without requiring users to sign in with an ArcGIS account. It supports API key or app authentication.Learn more that access ArcGIS Location ServicesArcGIS Location Services, also referred to as Location Services, are services hosted by Esri that provide geospatial functionality for developing mapping applications. They include the ArcGIS Basemap Styles service, ArcGIS Static Basemap Tiles service, ArcGIS Places service, ArcGIS Geocoding service, ArcGIS Routing service, ArcGIS GeoEnrichment service, and ArcGIS Elevation service. An ArcGIS Location Platform or ArcGIS Online account is required to use the services.Learn more and secure itemsAn item, also known as a content item, is a resource stored in a portal such as a web map, hosted layer, style, script tool, file, or notebook.Learn more.
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 accountAn ArcGIS account is an identity with a user type and set of privileges that can access specific ArcGIS products, tools, APIs, services, and resources. The main account types that can be used for development are an ArcGIS Location Platform account, ArcGIS Online account, and ArcGIS Enterprise account. ArcGIS Location Platform and ArcGIS Online accounts are also associated with a subscription.Learn more 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 credentialAPI key credentials are an item that contains the parameters used to create and manage long-lived access tokens for API key authentication. They are a type of developer credential.Learn more with the correct privileges to get an access token.

Go to the Create an API key tutorial and create an API keyAn API key is a long-lived access token created using API key credentials. They are valid for up to one year and are typically embedded directly into client applications.Learn more with the following privilege(s)Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS.Learn more:
- 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 credentialsAPI key credentials are an item that contains the parameters used to create and manage long-lived access tokens for API key authentication. They are a type of developer credential.Learn more access to the layer item. Learn more in Item access privileges.

Create a new OAuth credentialOAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential.Learn more to register the application.

Go to the Create OAuth credentials for user authentication tutorial to create an OAuth credential.
Copy the Client ID and Redirect URL from your OAuth credentials item and paste them to a safe location. They will be used in a later step.

Set developer credentials

Use the API key or OAuth developer credentialsDeveloper credentials are a type of item in a portal that contains parameters for authentication. There are two types of developer credentials: API key credentials and OAuth credentials.Learn more so your application can access ArcGIS servicesA service, also known as an ArcGIS service, is software that supports an ArcGIS REST API and provides geospatial functionality or data. A service can be hosted by Esri or in ArcGIS Enterprise.Learn more.

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 credentialsOAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential.Learn more.

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@v10.9.0/ol.css">
    <script src="https://cdn.jsdelivr.net/npm/ol@v10.9.0/dist/ol.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/ol-mapbox-style@13.4.1/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">
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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 layersA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more using GeoJSONGeoJSON is an open standard for representing geographic information in a JSON file. It is commonly used for sharing data between web services or manipulating vector data in the browser.Learn more, 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 attributionData attribution is the requirement to display the names of data source providers in all applications when accessing ArcGIS content, layers, or services.Learn more for the vector tile layer source.

Go to the Trailheads (Santa Monica Mountains) itemAn item, also known as a content item, is a resource stored in a portal such as a web map, hosted layer, style, script tool, file, or notebook.Learn more.
Scroll down to the Acknowledgments section and copy its value.

Paste the copied value to the attributions property.

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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) => {

      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 location services in these tutorials:

Map with polygons and features highlighted based on spatial relationships.

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.

Map of New York City showing a local data summary for a defined search area.

Get local data

Query regional facts and spending trends for a study area in the United States.

A web map displaying numerous point features scattered across the United States, representing data loaded from a GeoJSON source.

Add a feature layer as GeoJSON

Display and style GeoJSON features from a feature service.