Polar rose plot
A polar rose plot (or roseplot / rose diagram and sometimes a rhodonea plot) is an angle histogram showing the distribution of values grouped according to their numeric range (viewed as a "polar plot"). It is similar to a polar rose (i.e. with r = cos(k*θ)) but not necessarily symmetric, as the symmetry (or "direction" of petals) is entirely dependent on the input data.
A roseplot is useful for viewing the "direction" of input data. It is commonly used for plotting the daily (or yearly, etc.) average wind direction at a given location (sometimes called a "wind direction plot" or a "wind rose").
Roseplots display degree, radian, or grad data versus a radial axis. Like histograms, roseplots display statistical data, showing the number of occurrences of an event that fall within a specific angular region.
I routinely use roseplots in my bioinformatics research. They are especially useful for getting an overview of amino acid- or nucleotide-usage in a given genome or sequence (see figure).
Equations
The polar equation of the rose is
r = α*sin(nθ) ~OR~ r = α*cos(nθ)
If n is odd, the rose is n-petalled. If n is even, the rose is 2n-petalled. Integer values of n give the kind of roseplots described in this article.
Related R packages
- climatol — see rosavent: Wind-rose plot
