Removing the Primary X Axis and Keeping Only the Secondary Axis in ggplot
In this article, we’ll explore how to remove the primary x-axis from a ggplot plot while keeping only the secondary axis. This is achieved by using the dup_axis() function along with various configuration options provided by the scale_x_continuous() function.
Introduction
ggplot2 is a powerful data visualization library in R that offers a wide range of customization options to create complex plots. One of its strengths is the ability to create axis arrangements, including secondary axes. However, when working with ggplot2, it’s not uncommon to encounter situations where removing or hiding specific elements can improve the overall appearance and usability of your plot.
In this article, we’ll delve into the world of ggplot2’s axis customization options, focusing on how to remove the primary x-axis while keeping only the secondary axis.
Background
To understand how to achieve this goal, it’s essential to first explore the basics of axis configuration in ggplot2. The scale_x_continuous() function is used to create a continuous x-axis for a given data set. By default, this function creates an x-axis with all the tick marks and labels.
The dup_axis() function, introduced in ggplot2 version 0.9.0, allows us to duplicate one of the axes (either primary or secondary) while keeping it visible. This is particularly useful for creating axis arrangements where we want to keep only one set of tick marks and labels but still have a visual separation between two sets of data.
The Problem
When you create a plot with dup_axis(), ggplot2 adds the duplicated x-axis (or secondary y-axis, depending on the type of duplication) at the bottom or left side of the plot. However, if we want to remove only the primary x-axis, we need to use more advanced configuration options.
Solution
One approach to achieve this goal is by using various theme elements provided by the theme() function in ggplot2. By default, themes are used for overall styling and layout purposes, but they can also be employed to customize specific aspects of your plot.
In our example, we’ll use a combination of theme settings to remove the primary x-axis while keeping only the secondary axis.
Removing the Primary X Axis
To achieve this goal, we’ll use the theme() function in conjunction with various configuration options. Here’s an updated version of the original code snippet:
foo <- tibble(x = 1:100, y = rnorm(100))
ggplot(foo, aes(x = x, y = y)) +
geom_line() +
scale_x_continuous(sec.axis = dup_axis()) +
theme(
axis.text.x.bottom = element_blank(),
axis.ticks.x.bottom = element_blank(),
axis.title.x.bottom = element_blank()
)
In this updated code snippet, we’ve added a theme() block that specifies various configuration options to remove the primary x-axis. The settings used are:
axis.text.x.bottom = element_blank(): This setting removes all the text labels from the bottom of the x-axis.axis.ticks.x.bottom = element_blank(): This setting removes all the tick marks from the bottom of the x-axis.axis.title.x.bottom = element_blank(): This setting removes the title label from the bottom of the x-axis.
By using these settings, we’ve effectively removed the primary x-axis while keeping only the secondary axis. The resulting plot now has a clean and simplified appearance with only one set of tick marks and labels visible.
Using position to Remove X Axis
Another way to achieve this goal is by using the position argument in the scale_x_continuous() function.
Here’s an updated code snippet that demonstrates how to use position to remove the x-axis:
foo <- tibble(x = 1:100, y = rnorm(100))
ggplot(foo, aes(x = x, y = y)) +
geom_line() +
scale_x_continuous(position = "top")
In this updated code snippet, we’ve added a position argument to the scale_x_continuous() function. The value used is "top", which removes all the tick marks and labels from the bottom of the x-axis.
By using this approach, we’ve effectively removed the primary x-axis while keeping only the secondary axis.
Conclusion
In conclusion, removing the primary x-axis from a ggplot plot while keeping only the secondary axis can be achieved using advanced configuration options provided by the scale_x_continuous() function. By employing various theme settings and/or using the position argument, we can customize our plot to meet specific requirements.
In this article, we’ve explored two approaches to removing the primary x-axis in ggplot2: using dup_axis() along with theme settings and using position in the scale_x_continuous() function. Both methods offer flexible solutions for creating axis arrangements where only one set of tick marks and labels is desired.
References
Last modified on 2024-07-30