Aligning title in ggplot2

Question

I am working with the iris data-set to plot 'Sepal.Length vs Petal.Length'

ggplot(data=iris,aes(x=Sepal.Length,y=Petal.Length))+geom_point()+ggtitle("Sepal.Length vs Petal.Length")

Now, by default the title is left-aligned, how can I center align the title?

Answer 1

You can use the theme layer to center align the title. Below is the command solves your problem:

ggplot(data=iris,aes(x=Sepal.Length,y=Petal.Length))+geom_point()+ggtitle("Sepal.Length vs Petal.Length")+theme(plot.title = element_text(hjust = 0.5))

You can also change other parameters of the title such as font color and font style:

ggplot(data=iris,aes(x=Sepal.Length,y=Petal.Length))+geom_point()+ggtitle("Sepal.Length vs Petal.Length")+theme(plot.title = element_text(hjust = 0.5,colour = "blue",face = "bold.italic"))