> [!NOTE]
> **Note:** Starting in Looker 24.20, the Chart Config Editor supports the creation of dependency wheel charts.

A dependency wheel chart is similar to a [Sankey chart](https://docs.cloud.google.com/looker/docs/sankey-chart-config-editor), but a dependency wheel displays the flow between states around a circle rather than in a linear direction. In Looker, each dimension value is represented as a state, and the size of the flow is determined by a numeric measure value.

Using the [Chart Config Editor](https://docs.cloud.google.com/looker/docs/chart-config-editor), you can create dependency wheel charts by starting from a [column chart](https://docs.cloud.google.com/looker/docs/column-options) in Looker.

Dependency wheel charts require at least two dimensions and exactly one measure.

For example, you can create a dependency wheel chart that shows the **Order Item Count** measure values over several **Seasonal Collection** dimension values, which flow into **Category** dimension values. Each dimension value is represented by a color-coded arc on the outside of the circle. The width of a line connecting two arcs corresponds to the values of the **Order Item Count** measure for that dimension pair. The higher the value, the wider the line.
![](https://docs.cloud.google.com/static/looker/docs/images/wheel-2420.png)

## Prerequisites

To access the Chart Config Editor, you must have the [`can_override_vis_config` permission](https://docs.cloud.google.com/looker/docs/admin-panel-users-roles#can_override_vis_config).

## Writing the JSON snippet

To create a dependency wheel chart, start from the following JSON snippet:

    {
      chart: {
        type: 'dependencywheel'
      }
    }

## Creating a dependency wheel chart

To create a dependency wheel chart, follow these steps:

1. View a [column chart](https://docs.cloud.google.com/looker/docs/column-options) in an Explore, or edit a column chart in a Look or dashboard.

   Start from a column chart with at least two dimensions and exactly one measure. Your starting chart might look something like this example:

   ![Sample column chart with Category Name and Seasonal Collection on the x-axis and Order Items Count on the y-axis.](https://docs.cloud.google.com/static/looker/docs/images/sankey-base-2412.png)
2. Open the **Edit** menu in the visualization.

3. In the **Plot** tab, click the **Edit Chart Config** button. Looker displays the **Edit Chart Config** dialog.

4. Select the **Chart Config (Override)** section, and enter the HighCharts JSON from the [Writing the JSON snippet](https://docs.cloud.google.com/looker/docs/dependency-wheel-chart-config-editor#json) section of this page.

5. To let Looker properly format your JSON, click **\<\> (Format code)**.

6. To test your changes, click **Preview**.

7. To apply your changes, click **Apply**. The visualization will be displayed using the custom JSON values.

![](https://docs.cloud.google.com/static/looker/docs/images/wheel-json-2420.png)

Once you've customized your visualization, you can save it.

## Limitations and requirements

When you're using dependency wheel charts, keep the following limitations and requirements in mind:

- Dependency wheel charts require at least two dimensions and exactly one measure.
- Dependency wheel charts can display a maximum of 50 rows of data.
- Dependency wheel charts don't support pivoted dimensions.