Radar chart: Secret of success – #MM 13

Radar chart

This week I decided to take Makeover Monday little different than usual. The goal of this regular activity is to improve skills in data visualization by trying to retell the story of the original visualization more effectively or to find a new story in data.

This week was little bit different to me. When I saw the original chart, I couldn´t help myself but I wanted to create the same type of visualization in Tableau. I have never before created a radar chart combined with the background picture, so it was challenge I couldn’t refuse.

The dataset was simple, 2 dimensions (Social strata and Reason) and 1 measure (Rate). At first I had to find some clue how to create radar chart. Luckily I found a nice article on Tableau blog by Jonathan Trajkovic.

Calculation of X axis and Y axis

Thanks to trigonometry I can find formulas how to calculate values for both axes. Because I have 8 dimension values, I selected the appropriate formulas.

Unit circle angles color

x_asix

Y axis calculation

Before I started with the calculations above, I created calculation reason number to make my axes calculation easier (no need to write whole Reason name, but only use one digit number + then I can also sort the reasons).

reason

Creating visualization

  • Put calculation for X into columns and Y into rows
  • In Analysis menu unmark Aggregated measures
  • Show each social segment separately – put “Social Strata” into Colour

vizz1

  • Create the area between peaks – in Marks select Polygon
  • Tell Tableau in which order to connect the peaks – put “reason number” into Path

vizz2

Formatting visualization

When I finished the basic version of radar chart, I needed to polish it a little bit to make it understandable for the others.

  • Make the areas for each segment visible – reduce Colour opacity to 50%
  • Prepare some space for labels – set Fixed range for axes from -0,45 to 0,45
  • Remove axis marks from the visualization – hide Header for axis
  • Remove lines – set Grid line and Zero line for Sheet to None
  • Format tooltip – put “Social Strata”, “Reason” and “Rate” into Tooltip and format it little bit (as shown in picture)

format1

Adding the radar lines and dimensions labels

The last thing I needed, was to add background image with radar lines and dimensions labels.

  • With some drawing tool create an background image
  • In Map menu select Background image and click on Add image
  • Locate my background image and set values for axes

map

At the end I put the Sheet into Dashboard, added Legend and Headline and it was done.

Radar Chart

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