What is a nightingale rose chart?

A nightingale rose chart - also called a coxcomb chart or polar rose chart - arranges categories around a circle with equal angles, encoding each category's value as the length of its petal extending outward from the center rather than as a slice angle. It is named after Florence Nightingale, who popularized this chart style. Use it for a visually distinctive way to show proportion across a moderate number of categories.

What is the difference between Radius Mode and Area Mode?

Radius Mode (the default) keeps every category at an equal angle around the circle and varies each petal's length based on its value - this is the classic rose chart look. Area Mode keeps every category at a fixed outer radius and instead varies the angle each category occupies based on its value, which makes the chart functionally equivalent to a standard pie chart arranged in a circle. Choose Radius Mode for the visual rose effect; choose Area Mode if you want pie-chart-style proportions in a circular layout.

When should I use a nightingale rose chart instead of a pie chart?

Use a nightingale rose chart in Radius Mode when you want a visually distinct presentation - infographics, executive dashboards, or contexts where visual interest matters alongside the data. Use a Pie Chart when precise proportional comparison is the priority, since slice angle on a pie chart is a more universally understood encoding than petal length on a rose chart.

Is a nightingale rose chart harder to read than a pie chart?

Yes, for most viewers. Slice angle on a pie chart is a familiar, well-understood way to judge proportion. Petal length in Radius Mode is less intuitive and can visually exaggerate differences between categories, since petal area grows faster than petal length as the value increases. Use the tooltip and data labels to give viewers exact values rather than relying on them to judge petal length precisely.

What is the default size of the inner hole?

Inner Radius defaults to 20% and Outer Radius defaults to 90%, giving the rose a small hole at the center and petals that extend close to the edge of the chart container. Both are adjustable in Pie Radius.

Why does a small difference in value look like a big difference in petal size?

In Radius Mode, petal length is proportional to value, but petal area grows roughly with the square of the radius. A category with twice the value of another gets a petal with roughly four times the visual area, even though the underlying value only doubled. This is a known visual distortion of radius-encoded rose charts - rely on data labels or the tooltip for the actual values rather than judging by petal size alone.

Nightingale Rose Chart | Edilitics Docs

Show how a single measure breaks down into categories using petal length instead of pie slice angle - a visually distinct take on proportion.

A nightingale rose chart - also called a coxcomb chart or polar rose chart - arranges categories around a circle with equal angles, encoding each category's value as the length of its petal reaching outward from the center. Drop one categorical field into Column and one numeric field into Row. Use it for a visually distinctive presentation of proportion across a moderate number of categories, where the rose shape itself is part of the communication.

When to Use

The nightingale rose chart trades the familiar slice-angle encoding of a pie chart for petal length, in its default Radius Mode. This makes for a visually striking chart, but it is a less intuitive encoding for most viewers than a pie slice. Use it when visual distinctiveness matters - infographics, presentations, dashboards meant to stand out - more than precise, fast proportional reading.

Petal length exaggerates differences between categories. Because petal area grows faster than petal length as a value increases, a category with twice the value of another can visually appear to occupy four times the area. Viewers will likely overestimate the gap between a large category and a small one. Always pair this chart with visible data labels or a reliable tooltip so viewers can check the actual values rather than judging by eye.

Switch to a different chart when:

Precise proportional comparison matters more than visual distinctiveness - use Pie Chart
You have more than 8 categories - use Horizontal Bar
You want the equal-area, pie-like encoding without the rose visual - switch this chart to Area Mode, or use a Pie Chart directly
Categories are similar in size and need precise comparison - use Horizontal Bar

Scenario	Dimension	Measure
Causes of an incident by category	Incident category	Count of incidents
Monthly rainfall by season	Season name	Sum of rainfall mm
Survey responses by satisfaction level	Satisfaction level	Count of responses
Budget allocation by initiative	Initiative name	Sum of budget
Support tickets by issue type	Issue type	Count of tickets

Required Inputs

Field	Type	Count
Dimension	Categorical	Exactly 1
Measure	Numeric	Exactly 1

For step-by-step build instructions, see Build Your First Chart.

Formatting Options

The Format tab unlocks after at least one field is assigned. Once your chart is rendering, use these controls to define how it looks and how viewers interact with it.

Style

Use the chart title to state what the rose represents - viewers unfamiliar with this chart type need extra context compared to a standard pie chart.

Control	What it does
Show Chart Title	Shows or hides the title. The text is preserved when hidden so you can toggle it back without re-entering.
Enter Chart Title	Title text. Maximum 50 characters.
Font family	Font applied to the title.
Font size	5 to 30.
Bold / Italic	Weight and style.
Alignment	Left, center, or right within the chart container.

Pie Styles controls the color palette across petals, the rotation of the first petal, and the border between petals. Each petal also has a subtle rounded corner applied automatically, which is not user-adjustable.

Control	What it does
Start Color	The color applied to the first category's petal.
End Color	The color applied to the last category's petal. Petals in between are interpolated between Start and End. Each petal also has its own radial gradient, lighter near the center and full color near the outer edge.
Border Width	Thickness of the border drawn between petals, 0 to 10px. At 0, petals touch with no visible separator.
Border Color	Color of the border between petals. Only available when Border Width is greater than 0.
Border Type	Solid, Dashed, or Dotted. Only available when Border Width is greater than 0.

Pie Radius controls the inner hole size and how far petals extend outward.

Control	What it does
Inner Radius	Size of the inner hole as a percentage of the available space, 0 to 80%. Default is 20%.
Outer Radius	Maximum petal length as a percentage of the available space, 20 to 95%. Default is 90% - higher than a pie or donut chart, since the rose effect benefits from petals reaching close to the chart edge.

Rose Type is the control that defines this chart's behavior. It switches between two different encodings of the same data.

Mode	What it does
Radius Mode (default)	Every category sits at an equal angle around the circle. Each petal's length varies based on its value - this produces the classic rose shape.
Area Mode	Every category extends to the same outer radius. Instead, the angle each category occupies varies based on its value - this is functionally the same encoding as a standard pie chart, just arranged with a fixed petal length.

Switching to Area Mode removes the visual distinctiveness of the rose shape and produces a result very similar to a Pie Chart - if Area Mode is what you want, consider using a Pie Chart directly for a more familiar reading experience.

Pie Data Label controls what text appears on or near each petal and how it is formatted. Given how easily petal length can be misjudged visually, enabling labels is especially important on this chart type.

Control	What it does
Show Data Labels	Shows or hides labels on petals entirely.
Inside / Outside	Inside places the label within the petal - only readable on the longest petals. Outside places the label beyond the petal tip with a connecting line, the more reliable choice for shorter petals.
Auto Format Labels	When on, labels are automatically thinned if the category count exceeds Max Labels, preventing overlapping text on charts with many categories.
Max Labels	Maximum number of labels shown when Auto Format Labels is on, 1 to 100. Default is 24. Beyond this count, labels are skipped at a regular interval.
Show Percentage	Adds each category's percentage share of the total to its label.
Show Value	Adds each category's raw value to its label. Showing the raw value is especially useful on this chart type since petal length alone is easy to misjudge.
Number Type	Default, Scientific, Decimal, Currency, Percentage, or Custom. Applies when Show Value is on.
Display Unit	None, Thousand, Million, or Billion.
Decimal Places	0 to 6. Available when Number Type is not Default.
Font Family / Color / Font Size / Bold / Italic	Text styling for the label.
Text case	Uppercase, Lowercase, or Capitalize. Applies to the category name portion of the label and the legend.

The legend lists every category and helps viewers identify which color belongs to which petal.

Control	What it does
Show Legends	Shows or hides the legend. On by default, positioned to the right of the chart.
Vertical position	Top, middle, or bottom alignment of the legend block.
Horizontal position	Start, center, or end alignment.
Show Name	Default: labels always visible. On Hover: labels appear only when viewer hovers the legend.
Orientation	Vertical or Horizontal legend layout. Vertical is the default and works best alongside a circular chart.
Item Gap	Spacing between legend items.
Font Size	Legend label font size.
Color	Legend label text color.

Interactivity

The tooltip is the most reliable way for viewers to read exact values on this chart type, since petal length is hard to judge precisely by eye.

Control	What it does
Show Tooltip	Shows or hides the tooltip on hover. Keep on.
Background Color	Tooltip background color.
Headers / Values tabs	Separate styling for the category name row (Headers) and the value row (Values). The Values tab includes Number Type, Display Unit, and Decimal Places. The percentage row, when Show Percentage is on, follows the same header styling.

Keep animation on when the chart is first presented - the petals growing outward from the center draws attention to the relative differences as they form. Turn it off on dashboards that auto-refresh.

Control	What it does
Enable Animation	Turns the build animation on or off.
Duration	How long the animation runs, 0 to 3000ms. Default is 1000ms.
Delay	Time before the animation starts after the chart loads, 0 to 2000ms.
Easing Function	The motion curve. Cubic Out (the default) gives a natural deceleration.

Emphasis highlights the hovered petal, making it easier to track which petal corresponds to which part of the legend or tooltip.

Control	What it does
Show Emphasis	Enables or disables the hover effect.
Focus Type	Item: highlights the hovered petal and dims the rest. None: no visual change on hover.
Enable Scale	Scales the hovered petal slightly larger, making it visually pop from the rest of the rose.
Scale Size	How much the petal scales. Keep at 1.1 or below - large values can push the petal outside the chart boundary on a tightly cropped container.

Enable the Toolbox when viewers need to export the chart or inspect the exact values behind each petal.

Control	What it does
Show Toolbox	Shows or hides the toolbox icon bar.
Save as Image	Adds a download icon that saves the chart as a PNG.
Data View	Adds an icon that opens the underlying data table in the chart area.

Best Practices

Keep category count between 4 and 8. Below 4, the rose shape is not visually distinct from a simpler chart. Above 8, petals become narrow and hard to label, the same way a pie chart degrades with too many slices.

Always enable data labels or the tooltip. Petal length, especially in Radius Mode, is one of the harder visual encodings for viewers to judge precisely. Never rely on petal length alone to communicate a value - always give viewers the actual number through a label or tooltip.

Use Radius Mode for visual impact, Area Mode for familiar proportions. If the goal is a distinctive, eye-catching chart, keep the default Radius Mode. If you actually want pie-chart-style proportional reading but prefer the circular layout, switch to Area Mode - though at that point, a standard Pie Chart will usually communicate the same data more clearly.

Be aware that petal area, not just length, drives the visual impression. A category with twice the value of another will look like it occupies roughly four times the visual area in Radius Mode. This is inherent to the chart type, not a bug - account for it when deciding whether this chart fits your audience and message.

Reserve this chart for contexts where visual distinctiveness adds value. A nightingale rose chart on an operational dashboard that needs to be read quickly and accurately is usually the wrong choice. Save it for presentations, reports, or public-facing visuals where the unconventional shape itself communicates something - novelty, a sense of analysis depth, or simply visual variety.

FAQs

Need help? Email support@edilitics.com with your workspace, job ID, and context. We reply within one business day.

Nightingale Rose Chart