# ESRI 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.

## What you need

* OS Maps API added to an API project in the OS Data Hub with an API Key; see [Getting started with an API project](/os-apis/core-concepts/getting-started-with-an-api-project.md) for more information
* An ArcGIS Online account

## Instructions

{% stepper %}
{% step %}
**Add a new layer**

Once you've signed into your ESRI ArcGIS Online account and opened the map viewer.

* Select *Layers* > *Add* > *Add layer from URL*.

<figure><img src="/files/sf5XRbf2pT7YrnhSFi7O" alt="ArcGIS Online Layers dialog." width="316"><figcaption><p>ArcGIS Online Layers dialog.</p></figcaption></figure>
{% endstep %}

{% step %}
**Add an API and set up custom parameters**

In the Add Layer dialog:

* **URL**: Enter the base URL for OS Maps API, excluding the API Key. For example, <https://api.os.uk/maps/raster/v1/wmts>
* **Type**: Select *WMTS (OGC)*.
* Select *Custom request parameters* and enter the following:
  * **Parameter**: key
  * **Value**: \[Insert your OS API Key here]
* Click *Next*.

<figure><img src="/files/oUXnO8ydEBQb6FH5JviR" alt="ESRI ArcGIS Pro Add WMTS (OGC) Server Connection dialog with URL and custom request parameters set."><figcaption><p>ESRI ArcGIS Pro Add WMTS (OGC) Server Connection dialog with URL and custom request parameters set.</p></figcaption></figure>
{% endstep %}

{% step %}
**Adding layers to the map**

In the Add Layer dialog:

* Select a layer to add to the map
* Set the max feature limit
* Click *Add to map*.

<figure><img src="/files/JIWBzrV6c8dJ9Ji05k2d" alt="ArcGIS Online Add Layers dialog: Select a layer to add to map."><figcaption><p>ArcGIS Online Add Layers dialog: Select a layer to add to map.</p></figcaption></figure>

\_The layer will then display in the Layers panel and the data will display on the map:

<figure><img src="/files/7PRrNKtwtmVy1P0NoEnR" alt="ArcGIS Online UI showing OS Maps API in the map area."><figcaption><p>ArcGIS Online UI showing OS Maps API in the map area.</p></figcaption></figure>
{% endstep %}
{% endstepper %}


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