Stagger axis labels, new feature in ggplot2

Question

Hi there: I need to plot a factor with 81 different categories with different frequency counts each. Each factor name is a 4-letter category. It looks like this. As you ca

Answer 1

To stagger the labels, you could add spaces to the labels in the dataframe.

# Libraries
library(ggplot2)
library(stringi)

# fake data
set.seed(12345)
var <- stri_rand_strings(81, 4, pattern = '[HrhEgeIdiFtf]')
var1 <- rnorm(81, mean = 175, sd = 75)

out <- data.frame(var, var1)

# Add spacing, and set levels for plotting
out = out[order(out$var1), ]
out$var = paste0(out$var, c("", "       ", "            "))
out$var <- factor(out$var, levels = out$var[order(out$var1, decreasing = FALSE)])

# Plot
out.plot <- ggplot(out, aes(x = var, y = var1)) +
   geom_point() + coord_flip()
out.plot

Alternatively, draw the original plot, then edit. Here, I use the grid function, editGrob() to do the editing.

# Libraries
library(ggplot2)
library(gtable)
library(grid)
library(stringi)

# fake data
set.seed(12345)

var <- stri_rand_strings(81, 4, pattern = '[HrhEgeIdiFtf]')
var1 <- rnorm(81, mean = 175, sd = 75)

out <- data.frame(var, var1)

# Set levels for plotting
out$var <- factor(out$var, levels = out$var[order(out$var1, decreasing = FALSE)])

# Plot
out.plot <- ggplot(out, aes(x = var, y = var1)) +
   geom_point() + coord_flip()

# Get the ggplot grob
g = ggplotGrob(out.plot)

# Get a hierarchical list of component grobs
grid.ls(grid.force(g))

Look through the list to find the section referring to the left axis. The relevant bit is:

   axis-l.6-3-6-3   
     axis.line.y..zeroGrob.232   
     axis   
       axis.1-1-1-1   
         GRID.text.229   
       axis.1-2-1-2   

You will need to set up path from 'axis-l', through 'axis', through 'axis', though to 'GRID.text'.

# make the relevant column a little wider
g$widths[3] = unit(2.5, "cm")

# The edit
g = editGrob(grid.force(g), 
      gPath("axis-l", "axis", "axis", "GRID.text"), 
      x = unit(c(-1, 0, 1), "npc"), 
      grep = TRUE)

# Draw the plot
grid.newpage()
grid.draw(g)

Another option is to find your way through the structure to the relevant grob to make the edit.

# Get the grob
g <- ggplotGrob(out.plot)

# Get the y axis
index <- which(g$layout$name == "axis-l")  # Which grob
yaxis <- g$grobs[[index]]   

# Get the ticks (labels and marks)
ticks <- yaxis$children[[2]]

# Get the labels
ticksL <- ticks$grobs[[1]]

# Make the edit
ticksL$children[[1]]$x <- rep(unit.c(unit(c(1,0,-1),"npc")), 27)

# Put the edited labels back into the plot
ticks$grobs[[1]] <- ticksL
yaxis$children[[2]] <- ticks
g$grobs[[index]] <- yaxis

# Make the relevant column a little wider
g$widths[3] <- unit(2.5, "cm")

# Draw the plot
grid.newpage()
grid.draw(g)

Answer 2

Sandy mentions adding spaces to the labels. With a discrete axis, you can also simply add line breaks to alternate cases. In my case I wanted to stagger alternate ones:

scale_x_discrete(labels=paste0(c("","\n"),net_change$TZ_t)

Where net_change$TZ_t is my ordered factor. It extends to 'triple' levels easily with c("","\n","\n\n").