11/2/2020

Chapter 7 - Better Graphics

• demo(graphics) - a quick look at some of the available plots and visuals in R
• Graphics Devices
  • windows for Windows
  • quartz for Mac
  • X11 for Unix
• par() command
  • gives you a list of graphics parameters
  • you can get the values of particular graphics parameters, e.g., par("pch") shows you the default plotting character
  • can be used to change a graphics parameter for a graphics device
• Tip: It is useful to save your par() settings so that they can easily be reset.
• R uses MML (Mathematical Markup Language)
• To produce more permanent graphs (to a file, rather than a window or the screen) simply wrap the plotting command in code that opens and closes the relevant graphics device.
• Different types of graphics
  • Raster-style graphics - jpeg, png, bmp
  • Vector-style graphics - pdf, postscript, windows metafile
  • Many users prefer vector-style graphics because they are scalable
• Different options in R
  • Base graphics engine - not always convenient, especially for 3D and other sophisticated graphs
  • lattice package - Trellis graphics developed at Bell Labs
  • ggplot2 - based on The Grammar of Graphics, another very popular option
• See Graphics.R for lots of examples from Chapter 7

Please read Chapter 7 and begin Chapter 8 for class on Wednesday.