# ArcGIS Online

ArcGIS Online is a geographic information system (GIS) delivered using the software-as-a-service (SaaS) model. ArcGIS Online services are managed by Esri and accessed by a client running on a wide range of options.

These instructions demonstrate how to integrate and apply the OS Features API into ArcGIS Online in order to produce a series of topography layers based on our latest OS MasterMap Topography layer data.

## What you need

* Access to the ArcGIS Online service
* A preloaded base map, for example, [os-maps-api](https://docs.os.uk/os-apis/accessing-os-apis/os-maps-api "mention")
* OS Features added to an API project in the OS Data Hub; see [getting-started-with-an-api-project](https://docs.os.uk/os-apis/core-concepts/getting-started-with-an-api-project "mention") for more information

## Instructions

1. Login to ArcGIS Online. On the home page click *Map*.

   \_You will see an online map which could differ from the one shown below. This depends on your account settings.

   <figure><img src="https://osdatahub.os.uk/static/media/Online-1.751a2ae2.png" alt="ArcGIS Online UI showing a map"><figcaption></figcaption></figure>
2. Select *Add* > *Add Layer from Web*.

   <figure><img src="https://4043944746-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FoEzqrBzRGoJw7nQyLj1W%2Fuploads%2Fgit-blob-d4bde84028e298dd6f4442a92c175037ed91463d%2Fimage.png?alt=media" alt="ArcGIS Online UI showing Add > Add Layer from Web option"><figcaption></figcaption></figure>
3. In the Add Layer from Web dialog:
   * **What type of data are you referencing**: Select *A WFS OGC web service* in the dropdown.
   * **URL**: Enter the URL for the OS Features API without the API key.

     <figure><img src="https://4043944746-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FoEzqrBzRGoJw7nQyLj1W%2Fuploads%2Fgit-blob-e4b85cd3c5e1c1f7821c3e78d46ca3cf03f70bd5%2Fimage.png?alt=media" alt="ArcGIS Online Add Layer from Web dialog"><figcaption></figcaption></figure>
4. Click *Add Custom Parameters*.
5. In the parameters box:
   * Click \_Add Parameter.
   * **Parameter** column: Enter \_key.
   * **Value** column: Enter your actual OS Features API key. The Get Layers button becomes active when you enter this information.
6. Click *Get Layers,* select the layer you want to show in the dropdown and then click *Add Layer*. The dropdown lists all available layers from the OS Features service.

   <figure><img src="https://4043944746-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FoEzqrBzRGoJw7nQyLj1W%2Fuploads%2Fgit-blob-86393146e66fe977d4e93cf1073c8872aad46092%2Fimage%20(26).png?alt=media" alt="ArcGIS Online Add Layer from Web dialog showing Layers field options"><figcaption></figcaption></figure>
7. The selected layer now displays on top of the base map. In our example, the coordinate reference system does not need to be changed because the OS Features service serves the data in the same projection as the base mapping from ESRI which is Web Mercator.

   <figure><img src="https://4043944746-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FoEzqrBzRGoJw7nQyLj1W%2Fuploads%2Fgit-blob-ee4f4942cb620bfa2f38220628cacd2c50ce8671%2Fimage.png?alt=media" alt="ArcGIS Online showing selected OS Features API layers displaying on top of the base map."><figcaption></figcaption></figure>
8. You can style, query and inspect WFS data in the same way as other vector data.

   <figure><img src="https://4043944746-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FoEzqrBzRGoJw7nQyLj1W%2Fuploads%2Fgit-blob-ff24b878ba6c63e41f50a2b0954628259364cfef%2Fimage.png?alt=media" alt="ArcGIS online UI showing style, query and inspect WFS data options"><figcaption></figcaption></figure>