What are radial hierarchy charts and how to create one (with examples)
Understand how radial charts work – explore radial trees, sunburst diagrams, and when to use each
Radial hierarchy charts can look visually engaging at first glance, but they’re often misunderstood. When should you use one? And more importantly, what do they actually help your audience see?
In this guide, we’ll explain how radial hierarchy charts work, explore the difference between radial trees and sunburst diagrams, and show how to create your own in Flourish.
Jump to:
- What is a radial hierarchy chart?
- Radial hierarchy charts vs other charts
- Radial hierarchy charts vs other radial charts
- Radial tree vs sunburst diagrams
- How to create a radial hierarchy chart in Flourish
What is a radial hierarchy chart?
A radial hierarchy chart displays hierarchical data, but in a circular layout. Categories branch out from a central point, showing how parent groups break down into smaller child groups.
Instead of focusing on precise comparisons, these charts are designed to show structure – how data is organized and how different parts relate to each other.
There are two main types of radial hierarchy charts:
- Sunburst diagrams: use nested rings. Each ring represents a level in the hierarchy, and each segment represents a category. The size of each segment can also reflect value, making it possible to see both structure and proportion at the same time.
- Radial trees: use nodes and connecting lines arranged in a circular layout. They focus largely on relationships, showing how each node connects back to its parent.
How radial hierarchy charts differ from other charts
Radial hierarchy charts aren’t circular for pure aesthetics – their layout helps show how categories connect within a larger structure. Here is how they compare to other popular chart types:
Radial hierarchy charts vs bar charts
Bar charts focus on comparisons, using a linear axis to show values precisely. They tell you which category is larger or smaller, and by how much.
On the other hand, treemaps and other hierarchical charts show structure and proportion at the same time, using area to reveal how parts make up a whole — across multiple levels at once. The circular layout makes it easier to understand how subcategories relate back to a common root.
For example, if you want to compare sales across countries, a bar chart makes it easy to see that the US outsells Germany, and by exactly how much. Radial hierarchy charts trade that precision for structure. Rather than just ranking countries by sales, a radial chart shows how countries sit within regions — and how those regions make up the global total.
Radial hierarchy charts vs other radial charts
Not all radial charts show hierarchy.
Some circular charts – like radial bar charts or radar charts – focus on comparing values. They use a circular shape, but each segment or axis represents something separate. In other words, the categories don’t connect to each other – they’re just arranged in a circle.
Radial hierarchy charts are different because each category has a parent, and each branch links back to a central starting point.
Radial tree vs sunburst diagrams: What’s the difference?
Now that we’ve looked at how radial hierarchy charts differ from other chart types, the next question is: what’s the difference between the radial hierarchy charts themselves?
Both radial trees and sunburst diagrams are circular, and both show hierarchical data branching out from a central point. But they’re designed to show different things.
A radial tree focuses on structure. It shows how categories are connected, with each node linking back to a parent. The layout helps you follow relationships and understand how the data is organized. The circular shape doesn’t always represent a total.
A sunburst chart works differently. It still shows hierarchy, but it also encodes proportions. Each segment represents a share of its parent, and together they form a complete whole. The full 360° circle always represents a meaningful total.
How to create a radial hierarchy chart in Flourish
To create a radial hierarchy chart in Flourish, start by selecting a suitable template or uploading your data using Start with data.
Your data should already be structured hierarchically (parent – child – sub-child) in a wide format, where each row represents a single data point. In the Data tab, you can then choose how to order these levels to define the parent–child hierarchy in your treemap.
The order you select your columns in the Categories/nesting setting determines the hierarchy — the first column you choose becomes the parent, and each subsequent column becomes the next level down.
One of the benefits of the Flourish Hierarchy template is that you can easily switch between hierarchy formats directly in the editor. Explore whether your data works better as a sunburst or radial tree, or try a different nested structure like a treemap or packed circles.
From there, you can choose how many levels to show, set your series colors, and more. You can also add your chart to a Flourish story to step through different levels of the hierarchy and guide your audience through it – like the chart below.
Read more on our help doc.
