Display a map

Learn how to use OpenLayers to display a map.

Display a map using API key authentication

A map contains layers of geographic data. A map contains a basemap layer and, optionally, one or more data layers. You can display a specific area of a map by using a map view and setting the location and zoom level.

In this tutorial you will use OpenLayers to display a map of the Santa Monica Mountains in California using the Outdoor basemap layer.

This tutorial is the starting point for the other OpenLayers tutorials.

Prerequisites

An ArcGIS Location Platform or ArcGIS Online account.

Steps

Create a new app

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

Create a new CodePen app with a map div that is the full width and height of the browser window.

Go to CodePen and create a new pen for your application.

In CodePen > HTML, add HTML and CSS to create a page with a div element called map.

Use the HTML to create a page with a map. Use the map div to display the map. Use the CSS to make the map full width and height.

The <!DOCTYPE html> tag is not required in CodePen. If you are using a different editor or running the page on a local server, be sure to add this tag to the top of your HTML page.

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<html>

<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no" />
  <title>OpenLayers Tutorials: Display a map</title>

  <style>
    html,
    body,
    #map {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
      font-family: Arial, Helvetica, sans-serif;
      font-size: 14px;
      color: #323232;
    }
  </style>

</head>

<body>
  <div id="map"></div>

</body>

</html>

Create a new app by downloading the user authentication starter app and add a map div that is the full width and height of the browser window.

Download the user authentication starter app.
Unzip the folder and open it in a text editor of your choice, such as Visual Studio Code. The starter app includes the following:
- callback.html: This contains callback as part of the authentication process.
- index.html: This contains app logic and the OAuth 2.0 code necessary to perform the authentication.

In the index.html, add a div element called map.

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<body>

  <div id="map"></div>

Apply CSS styling to the map div.

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    html,
    body,

    #map {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
      font-family: Arial, Helvetica, sans-serif;
      font-size: 14px;
      color: #323232;
    }

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

Set developer credentials

Use the API key or OAuth developer credentials created in the previous step in your application.

Add <script> elements in the HTML <body> and create an accessToken variable to store your access token. Set YOUR_ACCESS_TOKEN with the access token you previously copied from your API key credentials.

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  <script>

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

  </script>
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In both the index.html and callback.html files, set the properties of clientId and redirectUri 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 script references

You will need add <script> and <link> tags to load the JavaScript and CSS files for OpenLayers and ol-mapbox-style.

In the index.html file, add the following <link> and <script> references if they are missing.

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  <style>
    html,
    body,
    #map {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
      font-family: Arial, Helvetica, sans-serif;
      font-size: 14px;
      color: #323232;
    }
  </style>

  <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"></script>

Create a map and view

Use the Map and View classes to create an OpenLayers map.

The OpenLayers Map class displays the contents of the map and provides a user interface to interact with it. It supports clicking, zooming, panning, rotating, and tilting the perspective of the map. It also lets you interact with the visible contents of the map data, for example finding features at the mouse cursor. You can also use it to modify the data displayed by adding new sources or changing layer properties. OpenLayers takes care of automatically re-rendering as needed in response to changes made to layers.

For further details, see the OpenLayers documentation.

Use the Map class to create the map with options to control its display and behavior. Set the target property to "map", which is the id of the div element.

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    const map = new ol.Map({ target: "map" });
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Create a View, and use setView to apply it to the map. To center the map view, set the center property to -118.80500,34.02700 and the zoom property to 13.

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    map.setView(
      new ol.View({
        center: ol.proj.fromLonLat([-118.805, 34.027]),
        zoom: 12
      })
    );
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Add the basemap layer

OpenLayers does not directly support a vector basemap or a vector style file, so you will use the openlayers-mapbox-style (olms) JavaScript library to load a Mapbox style from the Basemap styles service and render it with OpenLayers.

The Mapbox style is JSON file that contains a reference to the vector tile layers used in the style, and visual styling rules to apply to one or more data layers in those tiles.

Create a basemapId variable and set it to arcgis/outdoor.

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    const basemapId = "arcgis/outdoor";

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Construct the basemap URL based on basemapId and your API key.

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    const basemapId = "arcgis/outdoor";

    const basemapURL = `https://basemapstyles-api.arcgis.com/arcgis/rest/services/styles/v2/styles/${basemapId}?token=${accessToken}`;

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Use olms to apply the basemap style to your map. The olms function takes two inputs, the map element and the URL for a basemap layer.

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    const basemapId = "arcgis/outdoor";

    const basemapURL = `https://basemapstyles-api.arcgis.com/arcgis/rest/services/styles/v2/styles/${basemapId}?token=${accessToken}`;

    olms.apply(map, basemapURL)

      });
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Add attribution

You need to display Esri and data attribution in all applications that use Esri technology. OpenLayers displays data attribution automatically for the basemap styles service, however, you need to take additional steps to display Esri attribution ("Powered by Esri").

Add a load event handler to the olms function call. Inside, retrieve the basemap source and use setAttributions() to prepend Powered by Esri.

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    const basemapId = "arcgis/outdoor";

    const basemapURL = `https://basemapstyles-api.arcgis.com/arcgis/rest/services/styles/v2/styles/${basemapId}?token=${accessToken}`;

    olms.apply(map, basemapURL)

      .then(() => {
        // 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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