Taking time with visualisation
What it shows
A radar chart uses a radial (circular) display with several different quantitative axes emerging like spokes on a wheel to create a unique shape of quantitative values. Each axis represents a quantity for a different categorical value for the subject. You might see a radar chart being used in sport analysis, for example in football, to show a breakdown of the different attributes of a player’s performance or abilities. The various axes might show number of passes, number of shots, tackle % etc.
How to read it
The idea is that by plotting a value along each axis and then connecting up the resulting points a shape forms. First, identify what category each axis represents. Then assess how the categories are related to one another as you read around the wheel. Usually the ‘zero’ of each axis is the centre of the wheel. The further towards the edge of the spoke a point reaches, the higher the quantity. Then look at the whole shape: which features stand out? Are some categories more pronounced than others? Which categories are lacking?
Things to beware
It is important to pay more attention to the position of a shape along the axis than the connecting lines between axes. Sometimes categories may not have a real sequential link, but sometimes they may (e.g. in a radar chart that shows weather from month to month).