Add Color to Region Between Two Lines in ggplot2 Line Plot in R (2 Examples)

This article explains how to highlight the region between two ggplot2 lines with color in R.

The post consists of these content blocks:

So now the part you have been waiting for – the examples!

Example Data, Packages & Default Graphic

The following data is used as a basis for this R tutorial:

data <- data.frame(x = 1:5,          # Create example data frame
                   y1 = c(1, 3, 1, 4, 4),
                   y2 = c(5, 4, 4, 5, 7))
data                                 # Print example data frame

Table 1 shows the structure of the example data – It is constituted of five rows and three columns.

In this tutorial, we’ll also need to install and load the ggplot2 package.

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

Now, we can draw our data as shown below:

ggp <- ggplot(data, aes(x = x)) +    # Create default ggplot2 line plot
  geom_line(aes(y = y1)) +
  geom_line(aes(y = y2))
ggp                                  # Draw default ggplot2 line plot

As illustrated in Figure 1, we have plotted a ggplot2 line plot by running the previous code.

Example 1: Add Color Between Two Lines in ggplot2 Line Plot

This example explains how to fill the area between two ggplot2 lines.

For this task, we can use the R programming syntax below:

ggp +                                # Add color between lines
  geom_ribbon(aes(x = x,
                  ymin = y1,
                  ymax = y2),
              fill = "#1b98e0")

As shown in Figure 2, we have managed to create a ggplot2 line graph with blue color between the lines with the previous R programming code.

Example 2: Add Shading Between Two Lines in ggplot2 Line Plot

In Example 2, I’ll show how to draw a transparent gray shade between the lines of a ggplot2 graphic.

ggp +                                # Add shading between lines
  geom_ribbon(aes(x = x,
                  ymin = y1,
                  ymax = y2),
              fill = "gray",
              alpha = 0.4)

After running the previous R code the shaded region between our two lines visualized in Figure 3 has been drawn.

Video & Further Resources

Do you need more explanations on the R codes of the present article? Then I recommend watching the following video on my YouTube channel. In the video, I’m explaining the R code of this article.

Furthermore, you may have a look at some of the related R tutorials on https://statisticsglobe.com/. I have published several tutorials on topics such as text elements, colors, ggplot2, and graphics in R.

• Add Table to ggplot2 Plot
• Change Fill and Border Color of ggplot2 Plot
• Beginner/Advanced Tutorial for the ggplot2 Package
• Add Text to ggplot2 Plot in R
• Add Bold & Italic Text to ggplot2 Plot in R
• Graphics Overview in R
• Introduction to R Programming

Summary: In this tutorial, I have shown how to draw color between two lines in a ggplot2 plot in R programming. Please let me know in the comments below, if you have any additional questions. Furthermore, please subscribe to my email newsletter in order to receive regular updates on new articles.