A radar chart (also spider chart or star chart) is a possibility to visualize multivariate data. In a radar chart you have different categories and their metric values. In picture 1 the categories are the letters A to E and the values 0 to 6. Each category has his own axis. The axes are evenly arranged around the center. The distances along the axes represent the value of a category. The axes represent independent scales for each variable, which means they can have different scales for each variable. In the center of a radar chart the value is mostly “0”. The values of the categories are graphically connected with a line called radar line. A radar chart must have at least three different categories, because the connecting lines would otherwise interfere with the other. Radar charts provide grid lines, which connect the axes, if the radar chart has a common scale on each axis. The grid lines in a radar chart can be displayed as circles or polygons. A consumer can now see the value of a particular category, e.g. the value of category B is 3(picture 1). If you have more than one data row, the different data rows are marked with different colors (picture 2). Radar charts are good for comparing different categories, e.g. you can go ahead and compare sales of different products product sales by country.
Radar chart with markers:
You can mark individual data points, e.g. to see if a particular aim was reached or not.
Filled radar chart:
With a filled radar chart you can visualize data rows. The area of these data rows are filled with color.
all pictures in this article are self-made.