selective annotations

Author

Jen Richmond

Published

May 23, 2025

My friend Lisa called me with a ggplot challenge the other day. She was trying to work out how to have only some of her points labelled with annotations. Here are some notes about how you can label some points but not others.

load packages/make dataframe

Code

library(tidyverse)

## make up some data

df <- data.frame(
             level = as.factor(c("Level A", "Level A", 
                                 "Level B", "Level B", 
                                 "Level C", "Level C", 
                                 "Level D", "Level D",
                                 "Level E", "Level E")),
              gender = as.factor(c("Female","Male",
                                   "Female","Male",
                                   "Female","Male",
                                   "Female","Male", 
                                   "Female","Male")),
             score = c(12L, 23L, 13L, 20L, 16L, 18L, 15L, 20L, 11L, 22L)
      )

glimpse(df)

Rows: 10
Columns: 3
$ level  <fct> Level A, Level A, Level B, Level B, Level C, Level C, Level D, …
$ gender <fct> Female, Male, Female, Male, Female, Male, Female, Male, Female,…
$ score  <int> 12, 23, 13, 20, 16, 18, 15, 20, 11, 22

data setup

First, check that levels are behaving and then create new variables that contain just the values you want to print on your plot.

Code

levels(df$level)

[1] "Level A" "Level B" "Level C" "Level D" "Level E"

Code

df <- df %>%
  mutate(f_values = case_when(gender == "Female" ~ score), 
         m_values = case_when(gender == "Male" ~ score)) 

glimpse(df)

Rows: 10
Columns: 5
$ level    <fct> Level A, Level A, Level B, Level B, Level C, Level C, Level D…
$ gender   <fct> Female, Male, Female, Male, Female, Male, Female, Male, Femal…
$ score    <int> 12, 23, 13, 20, 16, 18, 15, 20, 11, 22
$ f_values <int> 12, NA, 13, NA, 16, NA, 15, NA, 11, NA
$ m_values <int> NA, 23, NA, 20, NA, 18, NA, 20, NA, 22

basic plot

Code

df %>%
  ggplot(aes(x = level, y = score, 
             colour = gender, group = gender)) +
  geom_point() + 
  geom_line() +
  scale_y_continuous(limits = c(0,30)) +
  theme_minimal()

plot with selective annotations

Here we have added two geom_text() calls, one for m_values and one for f_values. Unfortunately the values end up on top of the points.

Code

df %>%
  ggplot(aes(x = level, y = score, 
             colour = gender, group = gender)) +
  geom_point() + 
  geom_line() +
  scale_y_continuous(limits = c(0,30)) +
  theme_minimal() +
  geom_text(aes(label = m_values), size = 3) +
  geom_text(aes(label = f_values), size = 3)

Add a little vjust to shift the points up and down a little from the points. Don’t love what has happened to the legend though…

Code

df %>%
  ggplot(aes(x = level, y = score, 
             colour = gender, group = gender)) +
  geom_point() + 
  geom_line() +
  scale_y_continuous(limits = c(0,30)) +
  theme_minimal() +
  geom_text(aes(label = m_values), vjust = -2, size = 3) +
  geom_text(aes(label = f_values), vjust = 2, size = 3)

Adding show.legend = FALSE to let R know that I don’t want the text labels to appear in the legend.

Code

df %>%
  ggplot(aes(x = level, y = score, colour = gender, group = gender)) +
  geom_point() + 
  geom_line() +
  scale_y_continuous(limits = c(0,30)) +
  theme_minimal() +
  geom_text(aes(label = m_values), vjust = -2, size = 3, show.legend = FALSE) +
  geom_text(aes(label = f_values), vjust = 2, size = 3, show.legend = FALSE)

SUCCESS!