ggplot2 texts : Add text annotations to a graph in R software

 

 

http://www.sthda.com/english/wiki/ggplot2-texts-add-text-annotations-to-a-graph-in-r-software

 

• Install required packages
• Create some data
• Text annotations using geom_text and geom_label
• Change the text color and size by groups
• Add a text annotation at a particular coordinate
• annotation_custom : Add a static text annotation in the top-right, top-left, …
• ggrepel: Avoid overlapping of text labels
  • Scatter plots with text annotations
  • Volcano plot
• Infos

 

This article describes how to add a text annotation to a plot generated using ggplot2 package.

The functions below can be used :

• geom_text(): adds text directly to the plot
• geom_label(): draws a rectangle underneath the text, making it easier to read.
• annotate(): useful for adding small text annotations at a particular location on the plot
• annotation_custom(): Adds static annotations that are the same in every panel

It’s also possible to use the R package ggrepel, which is an extension and provides geom for ggplot2 to repel overlapping text labels away from each other.

We’ll start by describing how to use ggplot2 official functions for adding text annotations. In the last sections, examples using ggrepel extensions are provided.

Install required packages

# Install ggplot2
install.packages("ggplot2") # Install ggrepel install.packages("ggrepel")

Create some data

We’ll use a subset of mtcars data. The function sample() can be used to randomly extract 10 rows:

# Subset 10 rows
set.seed(1234) ss <- sample(1:32, 10) df <- mtcars[ss, ]

Text annotations using geom_text and geom_label

library(ggplot2)
# Simple scatter plot sp <- ggplot(df, aes(wt, mpg, label = rownames