Brief Introduction to {ggplot2}

This article covers information about the {ggplot2} package

Basics of plot()

The R engine can detect the type of the given data and create suitable plots accordingly.

df <- PlantGrowth # Load the data

plot(df$weight) # scatter plot of values in the order they appear
plot(df$group) # bar plot of frequency of each level
plot(x = df$group, y = df$weight) # boxplot for values of each level

Expansion

For charts like scatter plots, this gives us a nicer look because points are not located at the edge of the plotting area this way. To know more about this topic, check the following websites.

• https://schmidtpaul.github.io/dsfair_quarto/ch/summaryarticles/ggplot2intro.html#expand
• https://3mw.albert-rapp.de/p/change-axes-expansion

Miscellaneous

Does the order of the function call matters?

Usually it doesn’t. Only the order of the geom functions (e.g. geom_abline()) may influence the result.

How to add a photo for \(x\) tick?

Use ggtext

External resources

• ggplot2 official
• [About Facets]https://teunbrand.github.io/ggh4x/articles/Facets.html