The Grammar of Graphics is the language used to describe the various components of a graphic that represent data in a visualization. In this topic, you will learn more about the Grammar of Graphics and will use it to make plots. You wille-encounter some of the Grammar of Graphics terms used in the previous chapter.
We will now break down the Grammar of Graphics language, in order to understand the terms in greater detail.
In ggplot2, every plot is built up as a layer. Layers are made up of geometric objects (geoms), their statistical transformations (stats), and their thematic aspects. Hence, each plot can be thought of as a separate variable, in and of itself. Aesthetic mappings, defined withaes(), describe how variables are mapped to visual properties, or aesthetics. The following diagram depicts the use of the df and aes functions:
Let's look at an example. We will use the gapminder dataset. You can see the available variables in the following snippet...
