# 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 2*n*-petalled. Integer values of *n* give the kind of roseplots described in this article.

## Related R packages

- climatol — see
**rosavent**: Wind-rose plot