Creating a Composite Plot Using Patchwork in R

Introduction

The ggplot2 package in R is widely used for creating elegant and customizable visualizations. However, when multiple plots need to be arranged in a structured layout, additional packages like patchwork come in handy. This article demonstrates how to use patchwork to create a composite visualization consisting of three ggplot plots arranged in a 2x1 layout: two plots side by side and one below them.

Required Packages

To follow along with this tutorial, ensure that the following R packages are installed:

install.packages("ggplot2")

install.packages("patchwork")

After installation, load the libraries:

library(ggplot2)

library(patchwork)

Creating Individual Plots

We begin by creating three separate ggplot objects using the built-in mtcars dataset.

Creating Individual Plots

We begin by creating three separate ggplot objects using the built-in mtcars dataset.

# First plot: Weight vs MPG

p1 <- ggplot(mtcars, aes(x = wt, y = mpg)) +

  geom_point() +

  ggtitle("Plot 1: Weight vs MPG")

# Second plot: Horsepower vs MPG

p2 <- ggplot(mtcars, aes(x = hp, y = mpg)) +

  geom_point(color = "blue") +

  ggtitle("Plot 2: Horsepower vs MPG")

# Third plot: Displacement vs MPG

p3 <- ggplot(mtcars, aes(x = disp, y = mpg)) +

  geom_point(color = "red") +

  ggtitle("Plot 3: Displacement vs MPG")

Arranging the Plots Using Patchwork

The patchwork package makes it easy to combine these plots into a structured layout. To place p1 and p2 side by side and p3 below them, use the following syntax:

# Arrange the plots

layout <- (p1 | p2) / p3

# Display the composite plot

print(layout)

Explanation

• (p1 | p2): Places p1 and p2 next to each other horizontally.

• / p3: Places p3 below the first two plots.

• The patchwork package automatically manages spacing and alignment.

Customizing the Layout

Additional customization can be done using patchwork operators:

layout + plot_annotation(title = "Composite Plot using Patchwork",

                         subtitle = "A demonstration with mtcars dataset")

Conclusion

The patchwork package is a powerful tool for arranging multiple ggplot objects in R without requiring complex layout manipulations. It provides an intuitive syntax for structuring plots and is highly useful for creating publication-ready composite visualizations. Experiment with different layouts and styling options to enhance your graphical presentations in R.