Radial Diagrams

Radial Diagrams

Radial diagrams are a type of graph where values extend out from a central point; therefore they show the relationship of each variable to the central point/item.

They are useful because a number of different variables can be plotted and shown on the same graph, as more than one axis can be used. However using over four or five different variables can make a diagram quite complicated.

The most common form of this type of graph is a wind rose diagram, shown below, which shows the frequency of wind direction; the axis' represent North, South, East and West, and the number on each of the axis is the length of time that the wind was blowing in this direction. Therefore the prevailing wind direction can be easily shown.

Radial Diagrams are most commonly used to show the relationship of a variable to compass direction, ie they are used as directional diagrams, as shown in the wind rose diagram above where it shows the relationship of wind and compass direction. However they can be used to plot a rangs of variables.

They are advantageous because trends in the data set are clearly shown, with the variable with the largest value being highlighted on the graph. It is clear from the graph that the wind blows in an almost North South direction for much of the time.

The data that is applicable to this method is limited, but some data sets, such as compass direction, would be hard to present in any other way. It can also be hard to read exact values from the scale on the axis, as it often makes the diagram too crowded to include the scale; data often has a wide range of values when plotting a number of difffrent variables, meaning that it can be hard to find a suitable scale to use.