Radar diagram

The network diagram or spider web diagram , also star diagram , Kiviat or radar diagram , also smartspider graphic, is the graphical representation of values of several, equivalent categories in a spider web form . This diagram is particularly suitable for visualizing evaluations for previously defined criteria for two (or more) series.

There is an axis for each category . The same orientation applies to all axes; the better values are uniformly in the center or outside the rays.

The axes are evenly arranged in a circle in 360 degrees. The values of each series are connected with lines. Different colors are used for several series. The enclosed area is often filled in with color.

There must be at least 3 categories, since two of them all lie on top of each other and no connection would be visible. If there are more than 10 axes, the diagram becomes confusing. But even with fewer than 4 axes, the quantitative perception suffers due to the large distance to each other. Therefore the optimal number is between 5 and 7 axes.

Even if a comparative statement is possible for individual criteria, multidimensional sets can no longer be compared. An exception are quantities that are better / worse than a comparison quantity in all criteria. You are then Pareto optimal . In the network diagram, it completely encloses the comparison set.

Example: If the values in the diagram shown improve with increasing numbers, the blue line is Pareto-optimal compared to the red dotted line. The green curve is not Pareto-comparable.

The star diagram was first used by Georg von Mayr in 1877.

Individual evidence

↑ smartvote.ch : Description of the method - smartspider graphics. (PDF; 0.7 MB) June 2015, accessed on August 17, 2018 .
↑ Georg von Mayr: The Laws of Social Life (= The forces of nature. A natural scientific public library . Volume 23 ). Oldenbourg, Munich 1877, OCLC 459436998 , p. 78 .
↑ Michael Friendly : Milestones in the history of thematic cartography, statistical graphics, and data visualization. (PDF; 1.4 MB) 2008, accessed April 14, 2012 .

[1] smartvote.ch : Description of the method - smartspider graphics. (PDF; 0.7 MB) June 2015, accessed on August 17, 2018 .

[2] Georg von Mayr: The Laws of Social Life (= The forces of nature. A natural scientific public library . Volume 23 ). Oldenbourg, Munich 1877, OCLC 459436998 , p. 78 .

[3] Michael Friendly : Milestones in the history of thematic cartography, statistical graphics, and data visualization. (PDF; 1.4 MB) 2008, accessed April 14, 2012 .