The bar chart
After sketching several charts in ggplot I settled down on a map, a scatterplot and a bar chart. I tried to simplify the bar chart axes as much as I could, thinking about small things as the vertical lines that go along the chart. I also added an arrow to mark the difference between losing and winning votes.
Another small detail is the city label color. When the bars have a dark fill it’s white, but it switches to black when the background is lighter.
The scatterplot was more complicated. First, I used a log scale to dissipate differences between city sizes. Then I implemented a voronoi diagram to make the tooltip seamless. While a normal voronoi would trigger the tooltip at any distance from the nearest circle, I used a limited distance voronoi, which only triggers a mouse event when the user hovers near a circle.
I made other small decisions. There are some dots that suffer from occlusion. To be able to distinguish them while hovering I drew the border of the selected circle again, on top.
The map opens the piece and is crucial to understand the spatial angle of the story: the Socialists lost most of the vote in the biggest cities. It has a heavy annotation layer.