Adding text annotation with `geom_text()`, `geom_label()` or `annotate()`

Text is the most common kind of annotation. It allows to give more information on the most important part of the chart.

Using ggplot2, 2 main functions are available for that kind of annotation:

geom_text to add a simple piece of text
geom_label to add a label (framed text)

The annotate() function is a good alternative to geom_text() and geom_label() that can reduces the code length for simple cases.

# Libraries
library(ggplot2)
 
# Creation of dataset
annotation <- data.frame(
   x = c(2,4.5),
   y = c(20,25),
   label = c("label 1", "label 2")
)

# Left chart: using geom_text
p <- ggplot(mtcars, aes(x = wt, y = mpg)) + 
  geom_point() + theme_bw()
p + geom_text(data=annotation, aes(x=x, y=y, label=label), 
              color="orange", size=7 , angle=45, fontface="bold")

# Middle chart: using geom_label
p + geom_label(data=annotation, aes(x=x, y=y, label=label),
               color="orange", size=7 , angle=45, fontface="bold")

# Right chart: using annotate
p + annotate("text", x = c(2,4.5), y = c(20,25),
          label = c("label 1", "label 2") , color="orange",
          size=7 , angle=45, fontface="bold")

Adding text with `geom_text()` or `geom_label()`

This example demonstrates how to use geom_text() to add text as markers. It works pretty much the same as geom_point(), but add text instead of circles. A few arguments must be provided:

label: what text you want to display
nudge_x and nudge_y: shifts the text along X and Y axis
check_overlap tries to avoid text overlap. Note that a package called ggrepel extends this concept further

# Libraries
library(ggplot2)
library(dplyr)
library(tibble)
 
# Keep 30 first rows in the mtcars natively available dataset
data <- head(mtcars, 30)
 
# Add text with geom_text, use nudge to nudge the text
ggplot(data, aes(x=wt, y=mpg)) +
  geom_point() + # Show dots
  geom_text(
    label=rownames(data), 
    nudge_x = 0.25, nudge_y = 0.25, 
    check_overlap = T) + theme_bw()

geom_label() works pretty much the same way as geom_text(). However, text is wrapped in a rectangle that you can customize.

# Add text with geom_label, use nudge to nudge the text
ggplot(data, aes(x=wt, y=mpg)) +
  geom_point() + # Show dots
  geom_label(
    label=rownames(data), 
    nudge_x = 0.25, nudge_y = 0.25, 
    check_overlap = T,
    label.padding = unit(0.2, "lines"), # Rectangle size around label
    label.size = 0.05, color = "black",
    fill="#69b3a2") + theme_bw()

You can also select a group of marker and annotate them only. Here, only car with mpg > 20 and wt > 3 are annotated thanks to a data filtering in the geom_label() call.

# Change data rownames as a real column called 'carName'
data <- data %>%
  rownames_to_column(var="carName")
  
# Plot
ggplot(data, aes(x=wt, y=mpg)) +
  geom_point() + 
  geom_label( 
    data=data %>% filter(mpg>20 & wt>3), # Filter data first
    aes(label=carName)) + theme_bw()

Adding shapes with `annotate()`

The annotate() function allows to add all kind of shape on a ggplot2 chart. The first argument will control what kind is used: rect, segment or arrow for rectangle, segment or arrow.

# Add rectangles
p + annotate("rect", xmin=c(2,4), xmax=c(3,5), ymin=c(20,10) , ymax=c(30,20), alpha=0.2, color="blue", fill="blue")

# Add segments
p + annotate("segment", x = 1, xend = 3, y = 25, yend = 15, colour = "purple", size=3, alpha=0.6)

# Add arrow
p + annotate("segment", x = 2, xend = 4, y = 15, yend = 25, colour = "pink", size=3, alpha=0.6, arrow=arrow())

Adding ablines with `geom_hline()` and `geom_vline()`

An abline is a segment that goes from one chart extremity to the other. ggplot2 offers the geom_hline() and geom_vline() functions that are dedicated to it.

p +
  # horizontal
  geom_hline(yintercept=25, color="orange", size=1) +
  # vertical
  geom_vline(xintercept=3, color="orange", size=1)

Adding a point and a range with `pointrange()`

Last kind of annotation, add a dot and a segment directly with pointrange().

p + annotate("pointrange", x = 3.5, y = 20,
             ymin = 12, ymax = 28,
             colour = "orange",
             size = 1.5, alpha=0.4)

Text labels and annotation

Adding text annotation with `geom_text()`, `geom_label()` or `annotate()`

Adding text with `geom_text()` or `geom_label()`

Adding shapes with `annotate()`

Adding ablines with `geom_hline()` and `geom_vline()`

Adding a point and a range with `pointrange()`

Contact

Adding text annotation with geom_text(), geom_label() or annotate()

Adding text with geom_text() or geom_label()

Adding shapes with annotate()

Adding ablines with geom_hline() and geom_vline()

Adding a point and a range with pointrange()

Contact

Adding text annotation with `geom_text()`, `geom_label()` or `annotate()`

Adding text with `geom_text()` or `geom_label()`

Adding shapes with `annotate()`

Adding ablines with `geom_hline()` and `geom_vline()`

Adding a point and a range with `pointrange()`