I saw this radial graph the other day, and was impressed with its clarity and thr fact that it was developed by Florence Nightingale over 150 years ago.
When time-series data is plotted as a normal x-y plot with the time variable along the x-axis it is difficult to identify seasonality or other factors that may influence the data. Florence Nightingale used a form of radial plots to display data from the Crimean War that demonstrated the death rate amongst soldiers could be reduced by better hygiene practices.
Plotting the weekly numbers of deaths using this radial form demonstrates the variability during the first months of the year – For example, deaths from “Aussie flu” in the first weeks of 2018 can be observed. The increase in the number of deaths from the first week in April 2020 can clearly be seen. Click here full article.