Radar Charts! Sheena Ellenburg Outline • Overview – Characteristics – Nomenclature • Usage • Examples Overview - Characteristics • 2-D • 3 or more quantitative variables represented as axes starting from the same origin – Equi-angular spokes called radii – Lines drawn between points to form a polygon • Relative position and angle of the axes generally not informative Overview - Nomenclature • Also known as: – Web chart, cobweb chart (gridlines) – Spider chart (gridlines) – Star plot (no gridlines) – Irregular polygon – Polar chart (angular significance) – Kiviat chart (acceptable range bands) – Stardinates (Lanzenberger, 2003) Usage • Ideal Data: – Multivariate (mas que 3) – Many Quantitative to One Nominal • Sports players attributes, companies, coffee beans • Questions: – Which records/observations are most similar (clustering) – Which records/observations are dissimilar • Are there outliers? When to Use a Radar Chart • If you can’t accommodate different quantitative scales in a bar graph • If the objective if to compare symmetry rather than magnitudes – Stephen Few’s resort example • Data fits circular display intuitively (counter/clockwise reading order is either explicitly obvious, or is unimportant) – Clocked data – Coffee bean taste attributes Examples Spider/Web/Cobweb Chart Star Plot Polar Chart Kiviat Chart “Stardinates” [Lanzenberger, 2003]: Lanzenberger, M., "The Stardinates - Visualizing Highly Structured Data", Proceedings of the Seventh International Conference on Information Visualization (IV'03), 2003. Cupping Scores • SCAA Cupping Protocols • Sweet Marias Coffee Achives How to Taste an Oyster • Tomato - The insider's guide to food and drink in Melbourne European Sensory Network: Sensory Profiles of three German beers http://www.esn-network.com/635.html More examples of food research • http://www.cjbio.net/html/innovation/food_application.asp • http://www.sciencedirect.com/science/article/pii/S09503293 09000226 References • • • • • Kiviat Diagram: www2.cs.uidaho.edu Polar Chart: advsofteng.com Spider chart, star plot: wikipedia.org Stardinates: infovis-wiki.net Verghisgroup.com – 3 Things to Think About – A Warning Label for Radar Charts • Few, Stephen. Keep Radar Charts Below the Radar – Far Below. 2005. Perceptual Edge.