1. Use cases of radar chart

 

Workbook: Top Trumps Card Game Analysis (tableau.com)

This is a project from The Information Lab that visualizes the power levels of Marvel superheroes. Utilizing radar charts and area plots, it allows for a quick assessment of a hero’s overall strength. The shape of the radar chart aids in swiftly identifying the hero’s archetype, whether they are agile or strength-oriented, and so forth. When comparing two heroes, overlaying their respective radar charts proves particularly convenient.

 

2. Principles of Radar Charts

 

The default coordinate system in Tableau is a two-dimensional coordinate system, which switches to a geographic coordinate system only when using maps.

 

The radar chart is essentially a polar coordinate system where each feature occupies an angle, and the data is represented by the length of ‘r’. Our goal is to take the graph described in polar coordinates and plot it on Tableau’s default two-dimensional coordinate system. The overall approach for creating a radar chart involves a step-by-step translation process:

Raw data -> Polar coordinates -> Two-dimensional Cartesian coordinates

3. Build radar chart

 

3.1 Calculation field Angle that describes polar coordinates (raw data -> polar coordinates).

3.2 R of polar coordinates

3.3 Calculation field for X axis in two-dimensional coordinates

3.4 Calculation field for Y axis in two-dimensional coordinates

4. Constructing a Pentagon

 

4.1 By selecting a country to draw a pentagon. Drag the country into the filter, ensuring that only one country is retained in the filter.

4.2 Drag the Indicator into the Detail Marks card and set as descending order.

4.3 Modify the chart type of the Marks card to Polygon.

4.4 Drag the Angel field into the Path, computing using Indicator.

4.5 Drag the X and Y fields into the Columns and Rows respectively, and computing using Indicator.

5. Breakdown of calculation field Angle

 

RUNNING_SUM((2*PI())/MIN({COUNTD([Indicator])}))+PI()/2

MIN({countd([Indicator])}): To calculate the total number of indicator categories within the entire dataset, you can simply specify the number 5 if you are aware that there are only five analytical dimensions.

(2*PI())/: Divides the polar coordinates into five equal parts.

RUNNING_SUM: Accumulate angles based on the scoring perspective. 

+PI()/2: Control the starting point of polar coordinates.

 

6. Add & edit background

 

7. Beautify

 

Source of data: 2019/W5: Digital Economy and Society Index (DESI) – dataset by makeovermonday | data.world

Pujiang Zhang
Author: Pujiang Zhang

A recent graduate with a Master of Information Technology from the Queensland University of Technology with a literature background in digital media. My academic journey has fueled my passion for making informed decisions through data analysis, and I'm fascinated by the intersection of Artificial Intelligence and its societal impacts. Beyond the world of data, I find joy in activities like jogging and swimming. I also have a strong interstate in philosophy and history, dedicating my spare time to exploring the depths of these subjects.