Mapping the results of the French presidential elections 2nd round, may 2017
We use the results of the French presidential elections (2nd round, may 2017) to demonstrate the use of different interval classification techniques to create univariate choropleth maps of a continuous variable (the percentage of votes for different presidential candidates in municipalities).
Second, we present an isarithmic map of the election results which takes two continuous variables into account : the percentage of votes for the winning candidate and the number of inhabitants (population) of the municipality. The colouring of polygons (municipalities) by the winning candidate is weighted by the population of the entity. To account for the population of the municipalities, opacity is visually adjusted : high-population entities are fully opaque while municipalities with the lowest population are masked by the dark background.
Finally, we present a multivariate choropleth map. Each municipality is assigned a color hue that corresponds to the level of a categorical variable (which presidential candidate won the election in each municipality) and each entity’s hue is assigned a chromatic level that represents the intensity of a continuous variable (the percentage of votes for the winning candidate).