The Nightingale Rose Chart was first created by British nurse and statistician Florence Nightingale during the Crimean War of 1854-1856. At the time, field hospitals suffered from poor sanitary conditions, resulting in a soldier mortality rate as high as 42%, with most deaths attributed to infectious diseases rather than combat injuries. To visually demonstrate seasonal causes of mortality and persuade the government to improve medical care, Nightingale transformed the traditional histogram into a circular chart with a polar coordinate layout. Twelve sectors represented the months, with the length of the sector radius mapping the number of deaths, amplifying differences by the square of the area and radius. Blue, red, and black were used to distinguish between illness, combat injuries, and other causes of death.

1. Cyclical Adaptation
The circular structure naturally fits monthly, quarterly, and other cyclical data.
2. Difference Exaggeration Effect
The square relationship between radius and area makes the contrast between similar data more vivid.
3. Multi-Dimensional Encoding
Using color, radius, and sector-shaped subdivisions, it can simultaneously display information: category (e.g., cause of death), time (month), and number (number of deaths).
4. Balance of Aesthetics and Functionality
The "cockscomb"-like visual form is more appealing than traditional charts.

The Nightingale Rose chart is a type of pie chart. Traditional pie charts use the angles of the sectors to directly reflect the proportion of the parts to the whole, making them suitable for displaying static categorical relationships. The Nightingale Rose chart improves on the traditional pie chart by mapping values ​​to the length of the sector's radius. This uses the squared relationship between area and radius to amplify small differences, emphasizing the dynamic comparison of cyclical data (such as monthly fluctuations).

Public Health: During the Crimean War, Florence Nightingale used it to demonstrate monthly changes in soldier deaths from illness, combat injuries, and other causes, promoting healthcare reform. In modern epidemics, it can be used to compare the distribution of case types across different regions or time periods.
Business Analytics: Manufacturing uses quarterly fan radiuses to compare production capacity fluctuations, while the retail industry uses it to analyze holiday sales trends and assist in inventory decisions.
Customer Service: Displays the percentage of inquiries by type during daily peak hours. For example, if the "Account Issues" fan is prominent between 3:00 PM and 5:00 PM, targeted staffing can be deployed.