ggplot: Centre and move the vertical axis labels

Question

I'm looking to set up a mirrored bar chart with one set of axis labels in the middle. This image shows what I have so far (code to reproduce at the end):

I'd like the names to be centred between the charts. Methods tried:

using axis labels (best attempt shown here)
using annotation_custom (I found placing the labels to be very difficult and disliked the combination of ggplot references and base plot references)
creating a separate "chart object" to put into the grid.arrange panel (difficult to get the correct vertical spacing between labels without there being any bars)

I'd welcome any suggestions around the easiest way to achieve this layout. The base has to be ggplot, but happy to use other packages to arrange charts.

require("ggplot2")
require("gridExtra")

dataToPlot <- data.frame(
  "Person" = c("Alice", "Bob", "Carlton"),
  "Age" = c(14, 63, 24),
  "Score" = c(73, 62.1, 21.5))

plot1 <- ggplot(dataToPlot) +
  geom_bar(data = dataToPlot, aes(x = Person, y = Score), stat = "identity",
    fill = "blue", width = 0.8) +
  scale_y_continuous(trans = "reverse", expand = c(0, 0)) +
  scale_x_discrete(position = "top") +
  theme(
    axis.text.y = element_blank()
  ) +
  labs(x = NULL) +
  coord_flip()

plot2 <- ggplot(dataToPlot) +
  geom_bar(data = dataToPlot, aes(x = Person, y = Age), stat = "identity",
    fill = "red", width = 0.8) +
  scale_y_continuous(expand = c(0, 0)) +
  theme(
    axis.text.y = element_text(size = 20, hjust = 0.5)
  ) +
  labs(x = "") +
  coord_flip()

gridExtra::grid.arrange(plot1, plot2, ncol = 2, widths = c(1, 1.2))

Thank you - good spot. This centres them, but I also want to move them a little further from the axis. I'll post an updated image with the correct hjust value. — Serenthia, May 11 '17 at 14:50
You might need to adjust the value, but `element_text(size = 20, hjust = 0.5,margin=margin(r=30))` more or less works for me. — Andrew Gustar, May 11 '17 at 15:02
That's perfect - thank you. I hadn't known I could use margin in an `element_text` object. If you want to pop that line in an answer I'll accept it for your rep — Serenthia, May 11 '17 at 15:04
Or - even better - try setting `padding=0` in `grid.arrange` — Andrew Gustar, May 11 '17 at 15:05

score 4 · Accepted Answer · answered May 11 '17 at 15:07

4

There are two ways (perhaps in combination)...

Add a margin to the right of the axis labels in the right-hand chart...

element_text(size = 20, hjust = 0.5, margin=margin(r=30))

...or move the two charts closer together

grid.arrange(plot1, plot2, ncol = 2, widths = c(1, 1.2),padding=0)

answered May 11 '17 at 15:07

Andrew Gustar

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Note: `labs(x = NULL)` is also necessary in the left chart to remove any padding on that side – Serenthia May 11 '17 at 15:10

ggplot: Centre and move the vertical axis labels

1 Answers1