R graphics

Data Visualisation with R

Graphics 🖼️

• Graphics are commonly stored in a standard image format such as svg, jpg (or jpeg), png, pdf, and so on.
• When you view these graphics electronically, you would be using some graphical device to render the stored image.
• In R, the graphic is rendered by the graphical engine, grDevices (one of the core R package).

Graphics model in R

• Two main graphics model in R are implemented via two core packages:
  • graphics package, and
  • grid package.
• Plot using the graphics system is normally referred to as the base graphics.
• If the graphics is produced using the grid package, then it is using the grid graphics model.

Base graphics

• Base graphics are drawn via the graphics package and shown in display via the grDevices package

grid graphics

• The grid package contains low-level functions, i.e. draws only parts of the plot.
• This system gives a lot of control over the graphics, but requires the user to do a lot of work to draw a complete plot.
• You won’t be directly interacting with the grid package.
• Instead you’ll be using the ggplot2 package that provides high-level functions for plotting via the grid system.

Other graphical systems

• All other graphical systems are provided via contributed packages (i.e. you need to install it once to use it).
• The two most well known packages are:
  • lattice and
  • ggplot2.
• Both of these packages use the grid package to draw the plots.

Summary of R graphics