Rotating axis labels in R

Rotating axis labels is an important technique in data visualization to improve readability, especially when dealing with long labels. In ggplot2, you can easily adjust the appearance of these labels using the theme() function. By modifying the axis.text.x or axis.text.y elements within theme().

This article will help you know how you can adjust the angle and alignment of the labels easily.

Table of Contents:

• Rotating x-axis labels
• Rotating y-axis labels
• Comparing both x and y rotations
• Adjusting margins
  • Example with both notation
• Conclusion
• FAQs

Rotating x-axis labels

We can use the “theme()” function to rotate and modify the x-axis labels

p + theme(axis.text.x = element_text(angle = 45, hjust = 1))

Here, the “angle = 45” degrees (you can change this value to any other angle like 90,30..) rotates the x-axis labels by 45 degrees, and “hjust = 1” defines the horizontal adjustment. The ‘hjust’ parameter can take the following values:

• hjust = 1 will align the text to the right
• hjust = 0 will align the text to the left
• hjust = 0.5 will align the text to the center

Rotating y-axis labels

Similarly to rotate the y-axis labels we use the “theme()” function to rotate and modify the y-axis labels.

p + theme(axis.text.y = element_text(angle = 45, vjust = 1))

Here the ‘angle = 45’ rotates the y-axis labels by 45 degrees and vjust = 1 defines the vertical adjustment. The ‘vjust’ parameter can take the following values:

• vjust = 1 aligns the text at the bottom
• vjust = 0 aligns the text at the top
• vjust = 0.5 aligns the text at the center

Comparing both x and y rotations

If you want to rotate both x and y together, use:

p + theme(
axis.text.x = element_text(angle = 45, hjust = 1),
axis.text.y = element_text(angle = 45, vjust = 1)
)

The above code will rotate both the x-axis labels by 45 degrees with right alignment and the y-axis labels by 45 degrees with bottom alignment.

Adjusting margins

Sometimes, after rotating, the labels might overlap with the plot or other elements. You can use “margin()” to adjust the spacing around the axis labels:

p + theme( axis.text.x = element_text(angle = 45, hjust = 1),

plot.margin = margin(t = 10, r = 10, b = 10, l = 10)

)

This will increase the margin around the entire plot to avoid overlap.

Example with both notation

# Load ggplot2

library(ggplot2)

# Example dataset

data(mpg)

# Create the plot

p <- ggplot(mpg, aes(x = class, y = hwy)) +

  geom_boxplot()

# Rotate both axes' labels

p + theme(

  axis.text.x = element_text(angle = 45, hjust = 1, size = 12),

  axis.text.y = element_text(angle = 45, vjust = 1, size = 12)

)

Output:

Here size = 12 adjusts the font size of the labels where x-axis labels are rotated 45 degrees with right alignment and y-axis labels are rotated 45 degrees with bottom alignment.

Conclusion

Rotating axis labels in “ggplot2” helps to improve the readability of the plot. By using the theme() function, you can easily customize the rotation angle and alignment. This enhances the clarity of the visual representation and makes it more accessible and professional.

FAQs