Getting to grips with ggplot2

Abstract

We have made quite a few graphs already but only briefly explained how we did so, specifically using ggplot. We need a deeper understanding… hence this chapter. We focus on making graphs with ggplot2. The ggplot2 package can help us to produce quite complex visualizations, with elements such as graphical keys, without the need to write lines and lines of R code. It is, nevertheless, still flexible enough for us to tweak the appearance of a figure so that it meets our specific needs. This chapter describes the underlying principles of the grammar used in ggplot2, and then demonstrates various kinds of plots and modifications to plots that ggplot2 can implement.