While crunching numbers, a visual analysis of your data may help you get an overview of your data or compare filtered information at a glance. Aside from the built-in *graphics* package, R has many additional packages to help you with that.

We want to focus on **ggplot2** by Hadley Wickham, which is a very nice and quite popular graphics package.

Ggplot2 is based on a kind of statistical philosophy from a book I really recommend reading. In The Grammar of Graphics, author Leland Wilkinson goes deep into the structure of quantitative plotting. As a product, he establishes a rulebook for building charts the right way. Hadley Wickham built ggplot2 to follow these aesthetics and principles.