Understanding Scales in Facet Grid and Facet Wrap: A Key to Effective Faceting in ggplot2

Facet grid and facet wrap are two popular functions in ggplot2 for creating faceted plots. While they share some similarities, there are key differences in how they handle scales, which can significantly impact the appearance and behavior of your plot.

In this article, we’ll delve into the world of facets and scales, exploring why scales = "free" works differently for facet grid and facet wrap.

Facet grid and facet wrap are used to create faceted plots that display multiple datasets or variables side by side. The main difference between the two lies in how they arrange the facets: facet grid creates a grid of plots, while facet wrap places the facets next to each other.

Facet grid is ideal for creating faceted plots with multiple dimensions. It allows you to split your data into facets based on one or two variables that vary horizontally and/or vertically. The facet_grid function takes the following syntax:

ggplot(data, aes(x = x_variable, y = y_variable)) +
  geom_boxplot() +
  facet_grid(variable1 ~ variable2)

In this example, variable1 and variable2 are used to split the data into facets.

Facet wrap, on the other hand, is ideal for creating faceted plots with a single dimension. It places the facets next to each other, wrapping with a certain number of columns or rows. The facet_wrap function takes the following syntax:

ggplot(data, aes(x = x_variable)) +
  geom_boxplot() +
  facet_wrap(~ x_variable)

In this example, x_variable is used to split the data into facets.

When it comes to scales, both facet grid and facet wrap provide different options. The scales = "free" argument allows you to set the scale for each facet independently.

ggplot(data, aes(x = x_variable, y = y_variable)) +
  geom_boxplot() +
  facet_grid(. ~ variable1)

In this example, scales = "free" is used to split the data into facets based on variable1.

Facet wrap, when using scales = "free", allows each plot to be displayed independently. This means that there can be different x-axis and y-axis scales for each facet.

ggplot(data, aes(x = x_variable)) +
  geom_boxplot() +
  facet_wrap(~ x_variable, scales = "free")

In this example, scales = "free" is used to place the facets next to each other, wrapping with a certain number of columns or rows.

The reason why scales = "free" works differently for facet grid and facet wrap lies in how they arrange the facets. Facet grid creates a grid of plots, while facet wrap places the facets next to each other.

In facet grid, when scales = "free" is used, facets are bounded by the grid. This means that plots on the same row cannot have different y-axis, and there can only be a single x-axis for each column. Facet wrap, on the other hand, allows each plot to be displayed independently, which means that there can be different x-axis and y-axis scales for each facet.

Conclusion

In conclusion, while scales = "free" works differently for facet grid and facet wrap, it’s essential to understand how each function handles scales. By choosing the right function and scale option, you can create faceted plots that are both informative and visually appealing.

Best Practices

When working with facets and scales, keep the following best practices in mind:

Use facet_grid for creating faceted plots with multiple dimensions.
Use facet_wrap for creating faceted plots with a single dimension.
When using scales = "free", be aware that facets are bounded by the grid in facet grid and can be displayed independently in facet wrap.

By following these best practices, you can create high-quality faceted plots that effectively communicate your data insights.

Last modified on 2023-06-26

Understanding Scales in Facet Grid and Facet Wrap

Introduction to Facet Grid and Facet Wrap

Facet Grid

Facet Wrap

Scales in Facet Grid and Facet Wrap

Facet Grid with Scales = “free”

Facet Wrap with Scales = “free”

Why Does Scales = “free” Work Differently for Facet Grid and Facet Wrap?

Conclusion

Best Practices