Friday, September 27, 2019

Mapping Swiss Inequality

The Swiss broadcaster Schweizer Radio und Fernsehen (SRF) has released an interactive map to show the Unequal Distribution of Income in Switzerland. The broadcaster uses an interactive bivariate choropleth map to visualize both average incomes and income inequality across Switzerland.

Bivariate choropleth maps show two variables at once. Therefore sometimes they can be a little difficult to read. The two variables visualized on the SRF map are average incomes and income inequality. Here is what the colors represent:
  • Purple: areas with a high average income but a large gap between the low and high earners
  • Red: areas with a low income and a large gap between low and high earners
  • Grey: areas with a low income and a small gap between low and high earners
  • Blue: areas with a high income and small gap between low and high earners.
If you still find this too confusing you can simple hover over an individual canton on the interactive map to view the level of income inequality (expressed as a Gini coefficient score) and the average income.

According to the SRF analysis of the map areas with an average low income and low inequality (grey) are often found in rural areas. Areas with a low average income and high inequality (red) are often found in the areas of the country with high levels of tourism.

If you are interested in learning more about bivariate choropleth maps and how to make them then a good place to start is Joshua Stevens' Bivariate Choropleth Maps: A How-to Guide. Joushua's guide looks at the concept of making bivariate maps rather than provide a method for creating them with a specific tool.

If you want to know how the bivariate choropleth map above was made and how you can make your own then you might like Bivariate Maps with ggplot and sf. In this how-to guide Timo Grossenbacher and Angelo Zehr explain how the Unequal Distribution of Income in Switzerland map was made and provide a step-by-step guide to creating the map.

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