Elements of Grammar of Graphics

Components of a plot

The grammar of graphics with a short introduction clip can give us an idea of how various components can integrate together to form a plot. Let’s learn more about these components, their role, and how they are connected to the ggplot2 package.

It is an implementation as well as an extension of the grammar of graphics for the R language. The main idea is that we can create any basic plot from a combination of entities such as:

• Dataset (cleaned and processed) that defines the mapped points on the plot.
• Appearance, i.e., the look of the plot that specifies what the reader is supposed to focus on when reading the plot.
• Visual entities to differentiate between any categories and represent the mapped data to a given scale.

Therefore, the grammar of graphics provides users with an adaptable approach to thinking about how required graphics can be best constructed. This enables data analysts across different organizations to think out of the box when building visualizations rather than being restricted to a small number of graph types like bar graphs, line graphs, scatter plots, etc.

The ggplot2 package consists of the grammar of graphics implemented in R. Therefore, several graphical elements are layered on top of each other in the ggplot2 package to build a plot, and aesthetic mappings are used to refine these visualizations.

Approach to building a plot with layers

To create any new plot in the ggplot2 package, we need to think of this plot as made up of multiple layers. Each layer can be assumed to consist of either of the following:

• Some data of interest to the user.
• A relevant mapping of this data to aesthetics.
• A chosen geometry to present the data in a visual manner.

Sometimes, additional parameters can also be used to customize the graphic to add more information or to direct the user’s attention.

When combined correctly, these different layers can produce engaging and meaningful charts. Let’s gain a deeper understanding of these layers.