Wise Rose Calm Sector
The fraction of calm wind conditions is crucial information. This is often portrayed as a central circle in a wind rose, with the percentage clearly stated. Below a set threshold, wind direction is ignored and the sum total of wind speeds is used for this center circle.
This is currenly not well supported by the Wind rose charts, which limits its applicability. With a central calm sector, the chart would be even more useful for meteorological applications.
For an example, see:
Such a chart is possible to achieve by using the innerSize option. It is not available yet (currently on a master branch) but it will be available in the next release of Highcharts. It is a new property that, as the name suggests, allows to set the inner size for a pane (similarly to the pane's size option). In case when the innerSize is percentage, it is a percentage of the pane's size. Of course the calculation for the calm sector (also the percentage label) must be done by a user as the innerSize determines an empty area in the center of a pane only. Here is the example: https://jsfiddle.net/BlackLabel/x41gjr0z/.