Reverse geocode | OpenLayers

Learn how to find an address near a locationA location is a position or region (point, line, or polygon) on the earth's surface.Learn more.

Reverse geocode coordinates to addresses with the Geocoding service using API key authentication

Reverse geocoding is the process of converting a locationA location is a position or region (point, line, or polygon) on the earth's surface.Learn more to an address or placeA place, also known as a point of interest (POI), is a location that represents a business, administrative entity, or geographic feature around the world. A place can also have attributes associated with it, such as a name, address, category, and ID.Learn more. To reverse geocode, you use the ArcGIS Geocoding serviceA geocoding service is a service that can search for addresses, place addresses, businesses, reverse geocode coordinates to addresses, provide suggestions for places, and perform bulk geocoding. It is hosted by Esri as the ArcGIS Geocoding service and can also be hosted in ArcGIS Enterprise.Learn more and the reverseGeocode operation. This operation requires an initial location and returns an address with attributes such as place name and location.

In this tutorial, you use the reverseGeocode method of ArcGIS REST JS to reverse geocode and find the closest address to your clicked location on the map.

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
  - Location services > Geocoding

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 references

This tutorial uses ArcGIS REST JS for reverse geocoding, and the ol-popup library to display pop-ups.

In the <head> element, add references to the ArcGIS REST JS and ol-popup libraries.

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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/@esri/arcgis-rest-request@4/dist/bundled/request.umd.js"></script>
    <script
      src="https://unpkg.com/@esri/arcgis-rest-geocoding@4/dist/bundled/geocoding.umd.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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Update the map

An arcgis/navigation basemap styleA basemap style is a definition that controls the visual appearance of how geographic data in a basemap are displayed. It includes colors, backgrounds, outlines, labels, and other visual elements. Each basemap style emphasizes a specific type of cartographic theme and data.Learn more is typically used in geocoding and routing applications. Update the basemap layer to use the style.

Update the basemap and the map initialization to center on location [2.3522,48.8566], Paris.

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    <script>

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

    // or

    /* Use for user authentication */
    // const session = await arcgisRest.ArcGISIdentityManager.beginOAuth2({
    //   clientId: "YOUR_CLIENT_ID", // Your client ID from OAuth credentials
    //   redirectUri: "YOUR_REDIRECT_URI", // The redirect URL registered in your OAuth credentials
    //   portal: "YOUR_PORTAL_URL" // Your portal URL
    // })

    // const accessToken = session.token;

    const map = new ol.Map({
      target: "map"
    });

    const view = new ol.View({

      center: ol.proj.fromLonLat([2.3522, 48.8566]), // Paris

      zoom: 12
    });
    map.setView(view);

    const basemapId = "arcgis/navigation";

    olms.apply(map, `https://basemapstyles-api.arcgis.com/arcgis/rest/services/styles/v2/styles/${basemapId}?token=${accessToken}`).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);

    });

    </script>
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Add a pop-up

Create a Popup to display the results of the reverse geocode. It is a type of Overlay so you add it to the map with map.addOverlay.

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

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    const view = new ol.View({

      center: ol.proj.fromLonLat([2.3522, 48.8566]), // Paris

      zoom: 12
    });
    map.setView(view);

    const popup = new Popup();
    map.addOverlay(popup);
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Add click event handler

Before you call the reverse Geocoding service, you need the location of the clicked point. Use ol.proj.transform to convert this into a latitude and longitude.

Add a click handler to the map. Inside, convert the clicked coordinates from the event object into latitude and longitude.

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

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

      const coords = ol.proj.transform(e.coordinate, "EPSG:3857", "EPSG:4326");

    });
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Call reverse geocode service

Use the ArcGIS REST JS reverseGeocode method to find an address closest to a point.

Inside the click handler, create a new arcgisRest.ApiKeyManager to access the Geocoding service. Call the arcgisRest.reverseGeocode method with the coordinates array.

Security and authentication guide
You need an access tokenAn access token is an authorization string that provides access to secure ArcGIS content, data, and services. Its capabilities are determined by the privileges it supports. It is obtained by implementing API key authentication, User authentication, or App authentication.Learn more to 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 with ArcGIS REST JSArcGIS REST JS is a collection of JavaScript modules that can access ArcGIS location services and ArcGIS Enterprise services.Learn more. To learn more, go to How to use authentication .
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      const coords = ol.proj.transform(e.coordinate, "EPSG:3857", "EPSG:4326");

      const authentication = arcgisRest.ApiKeyManager.fromKey(accessToken);

      arcgisRest
        .reverseGeocode(coords, {
          authentication
        })
```
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Display the result

The response from the reverseGeocode operation contains two properties. address is a structured object with fields such as street name and business name. location contains the locationA location is a position or region (point, line, or polygon) on the earth's surface.Learn more of the returned address, which may differ from the coordinates you provided. Display these values in a pop-up. Use a catch handler to check for errors accessing the service.

Add a then handler. Use popup.show to display the resulting address and coordinates.

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      arcgisRest
        .reverseGeocode(coords, {
          authentication
        })

        .then((result) => {
          const message =
            `${result.address.LongLabel}<br>` + `${result.location.x.toLocaleString()}, ${result.location.y.toLocaleString()}`;

          popup.show(e.coordinate, message);
        })
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Add a catch handler. In most cases, errors occur when the user clicks in the water, so simply hide the pop-up when this happens. Use popup.hide() to remove the pop-up and then write the error to the console.

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          popup.show(e.coordinate, message);
        })

        .catch((error) => {
          popup.hide();
          console.error(error);
        });
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Run the app

Run the app.

Click on the map to reverse geocode the clicked point and display a pop-up with the closest address and coordinates.

What's next?

Learn how to use additional location services in these tutorials:

Map showing address autosuggest results and a selected location in Vancouver.

Search with autosuggest

Search for addresses with partial text using autosuggest.

A map of San Francisco with multiple blue location markers representing nearby places.

Find place addresses

Search for places by category near a location.

Map showing a calculated driving route through downtown Toronto with turn‑by‑turn directions.

Find a route and directions

Find a route and directions from a start and finish location.