Values and angles visualization — Part 1

The first option, when trying to relate angles that vary in time, is to be able to reveal the distribution of these angles. This is exactly what the distribution radar chart proposes to do. It is a simple and effective way to compare the measurement frequency of an angle over a defined time.
As we talk about weather, rather than presenting data in a frequency table, it is better to represent these data in a “radar” which materializes the values that can take this angle on a 360° arc. Whether it is a wind direction or source, or a strike bearing, the angle always refers to a compass reading. And the representation in the form of a virtual compass (the radar) remains the most effective.

The distribution radar chart allows to visualize how the angles are distributed over a given period of time. The values it displays represent the frequency at which an angle value is measured. The further one point is from the center of the radar, the more this value is present in the measured values, in comparison with other angle values. The vertical scale, which is a percent scale, indicates the contribution of an angle value to the whole of the measurements set. For example, for a wind source, a 50% point at W-NW shows that, over the given period, half of the winds came from W-NW.

To set this chart, you must first select the modules and the measurements you want to compare. You can select up to four angles and, in historical data, you can choose the most appropriate dataset (average, median or middle, regarding the compilation mode you’ve set).
In the first angle parameters, you can set the number of sectors on which you want a representation of this distribution. Allotment is done for 4, 8 or 16 sectors.

For example, the following graph highlights the relative participation of winds sources (winds and gusts) for the 2018 summer at my home. Note that if you hover over an area with your mouse cursor, the legend in the upper left corner indicates the type of the measure being represented.

As you can see, although little used in meteorology, the distribution radar chart allows to “visualize” the angular distribution of certain types of measurements. It makes it possible to highlight, possibly, a first level of correlation between angular values, but does not allow to show this potential correlation for other types of measurements. So I’m making an appointment with you to discover right here, in a few days, the complete radar map that allows such a visualization.