Map of European Countries with Ratio of Sustainable vs Unsustainable Power Plants


I am a Swansea University Student and I have been asked to produce a visualization of the global power plant dataset, below is one of my visualizations.




Visual Design Type: Symbol Map

Name of Tool: Tableau

Country: United Kingdom, France, Germany, Spain, Portugal, Luxembourg, Belgium, Italy, Netherlands

Year: 2019

Visual Mappings:
* X-Axis: Latitude (Generated)
* Y-Axis: Longitude (Generated)
* Detail: Country
* Colour: AVG(Sustainable)

Unique Observation: Belgium and Luxembourg have the worst sustainability ratios when compared with the other countries, France has the highest.

Data Preparation: Calculated field added called Sustainable to determine if primary fuel of power plant is sustainable. Formula = (IF [primary_fuel] = “Hydro” OR [primary_fuel] = “Biomass” OR [primary_fuel] = “Wind” OR [primary_fuel] = “Solar” THEN 1 ELSE -1 END)


  • Does the legend and title make it clear what the visualization is showing?
  • Is the scale for sustainability suitable? Scale is (-1 to 1).
  • Would there be another map visualization type more suitable?

Thank you for reading.

If [-1, 1] is the whole range, one should show this in the colour map legend. Otherwise it is difficult to compare the map for different periods when the legends change frequently.

I guess that your class lecturer/professor may want students to explore more variables. Once you have considered more variables, you may find a good answer to your last question.

I do not understand how your formula relates to the colour map. Your formula produces either 1 or -1, there must be other formulae.

Regarding to the scale of sustainability I would try a normalization i.e. x-min(x)/(max(x)-min(x) so the numbers to be between 0 and 1. Moreover, Try to add steps in your legend like 5 or 7 based on the values you have got so the changes might be more distinct.

To do so try: Right click on legend -> Edit Colour -> Add steps