Changing font size and direction of axes text in ggplot2

Question

I am plotting a graph with a categorical variable on the x axis and a numerical variable on the y axis.

For the x axis, given that there are many data points, the default text formatting causes the label for each tick mark to overlap with other labels. How do I (a) change the font size for my axis text and (b) change the orientation of the text so that the text is perpendicular to the axis?

Answer 1

To change the font size and direction of the axes, add the following function to your plot:

theme(text = element_text(size=15),axis.text.x = element_text(angle=90, hjust=1)) 

angle rotates the text, and hjust controls the horizontal justification.

For example:

data(iris)

ggplot(iris, aes(x=Species, y=Sepal.Length)) +

  geom_jitter(width = 0.1, alpha = 0.5) +

  theme(text = element_text(size=15),axis.text.x = element_text(angle=90, hjust=1)) 

Output: