9.6 Hiding Grid Lines

9.6.1 Problem

You want to hide the grid lines in a plot.

9.6.2 Solution

The major grid lines (those that align with the tick marks) are controlled with panel.grid.major. The minor grid lines (the ones between the major lines) are controlled with panel.grid.minor. This will hide them both, as shown in Figure 9.11 (left):

library(gcookbook)  # Load gcookbook for the heightweight data set

hw_plot <- ggplot(heightweight, aes(x = ageYear, y = heightIn)) +
  geom_point()

hw_plot +
  theme(
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank()
  )

9.6.3 Discussion

It’s possible to hide just the vertical or horizontal grid lines, as shown in the middle and right-hand graphs in Figure 9.11, with panel.grid.major.x, panel.grid.major.y, panel.grid.minor.x, and panel.grid.minor.y:

# Hide the vertical grid lines (which intersect with the x-axis)
hw_plot +
  theme(
    panel.grid.major.x = element_blank(),
    panel.grid.minor.x = element_blank()
  )

# Hide the horizontal grid lines (which intersect with the y-axis)
hw_plot +
  theme(
    panel.grid.major.y = element_blank(),
    panel.grid.minor.y = element_blank()
  )

Figure 9.11: No grid lines (left); No vertical lines (middle); No horizontal lines (right)