This is a circular histogram plot which displays directional data and the frequency of each class. It is widely used in geography, geology and other earth sciences.
This type of graph is a modification of the histogram In the example, the distribution of the treatment outcome for an arthritis blind trial conducted in 1988 is plotted against age.
Tukey's hanging rootogram
This visualisation is a variation of the concept of histograms, combining observed and predicted distributions in a simple way.