R Cookbook, 2nd Edition

Chapter 10. Graphics

Graphics is a great strength of R. The graphics package is part of the standard distribution and contains many useful functions for creating a variety of graphic displays. The base functionality has been expanded and made easier with ggplot2, part of the tidyverse of packages. In this chapter we will focus on examples using ggplot2, and we will occasionally suggest other packages. In this chapter’s See Also sections we mention functions in other packages that do the same job in a different way. We suggest that you explore those alternatives if you are dissatisfied with what’s offered by ggplot2 or base graphics.

Graphics is a vast subject, and we can only scratch the surface here. Winston Chang’s R Graphics Cookbook, 2nd ed., is part of the O’Reilly Cookbook series and walks through many useful recipes with a focus on ggplot2. If you want to delve deeper, we recommend R Graphics by Paul Murrell (Chapman & Hall); it discusses the paradigms behind R graphics, explains how to use the graphics functions, and contains numerous examples, including the code to re-create them. Some of the examples are pretty amazing.

The Illustrations

The graphs in this chapter are mostly plain and unadorned. We did that intentionally. When you call the ggplot function, as in:

library(tidyverse)

df <- data.frame(x = 1:5, y = 1:5)
ggplot(df, aes(x, y)) +
  geom_point()

you get a plain graphical representation of x and y as shown in Figure 10-1.

Figure 10-1. Simple plot

You could ...