Combine Two ggplot2 Plots from Different Data Frames in R (Example)

In this article you’ll learn how to draw a ggplot2 plot based on several different data sources in the R programming language.

Table of contents:

Let’s do this…

Example Data, Add-On Packages & Default Plot

Consider the following example data:

data1 <- data.frame(x = 1:5,        # Create first data frame
                    y = 1:5)
data1                               # Print first data frame
#   x y
# 1 1 1
# 2 2 2
# 3 3 3
# 4 4 4
# 5 5 5
data2 <- data.frame(x = 2:6,        # Create second data frame
                    y = 8:4)
data2                               # Print second data frame
#   x y
# 1 2 8
# 2 3 7
# 3 4 6
# 4 5 5
# 5 6 4

The previous RStudio console output shows the structure of our example data sets – Both data frames contains two numeric columns with the variable names x and y.

If we want to use the functions of the ggplot2 package, we also have to install and load ggplot2:

install.packages("ggplot2")         # Install ggplot2 package
library("ggplot2")                  # Load ggplot2 package

Now, we can move on to the example…

Example: Drawing ggplot2 Plot Based on Two Different Data Frames

This Section shows how to use the ggplot2 package to draw a plot based on two different data sets.

For this, we have to set the data argument within the ggplot function to NULL. Then, we are specifying two geoms (i.e. geom_point and geom_line) and define the data set we want to use within each of those geoms.

ggp <- ggplot(NULL, aes(x, y)) +    # Draw ggplot2 plot based on two data frames
  geom_point(data = data1, col = "red") +
  geom_line(data = data2, col = "blue")
ggp                                 # Draw plot

Figure 1 visualizes the output of the previous R code – A ggplot2 graph created based on multiple different data matrices.

Video, Further Resources & Summary

If you need more information on the R programming codes of this article, you may watch the following video of my YouTube channel. In the video, I illustrate the content of this article.

The YouTube video will be added soon.

Furthermore, I can recommend to have a look at some of the other tutorials of this homepage:

• Draw Unbalanced Grid of ggplot2 Plots
• Arrange List of ggplot2 Plots
• Add Common Legend to Combined ggplot2 Plots
• R Graphics Gallery
• The R Programming Language

Summary: In this article, I explained how to create a ggplot2 graph with two different data sets in the R programming language. Let me know in the comments section, in case you have additional questions.