1. The Grammar of Graphics
Using ggplot2 to create informative and beautiful graphics in R, easily

2. Introduction The painful process of creating graphs in SPSS
Creating complicated graphs in SPSS is possible, but very tedious.
Total time; ~12 hours.
Hard to change details
Figure 19; Reforms (t0) by attitudes on Redistribution, within EVS waves.
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3. Plotting in R
The basic R functions create functional plots, but are again quite limited.
Creating trellis plots for complicated datasets with various graphical layers is time-consuming and requires programming experience.
Lattice helps, and can be used to create anything you might desire…
However, this will probably require writing custom panel functions, and can become difficult very quickly.
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4. The Grammar of Graphics
Leland Wilkinson’s approach
Created by Leland Wilkinson, when working (ironically) for SPSS
Ggplot2 is a (sometimes loose) implementation in R by Hadley Wickham
Create plots not by choosing a chart, but by rules about the building blocks that make a graphic, written in the ‘grammar’ of graphics.
Make graphics easier
Grammar instead of preset plots facilitate innovative display options
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5. Example What is a pie chart?
How would you describe a pie chart to someone who has never seen one?
A pie chart is a stacked barchart with polar coordinates
With ggplot, the difference is “+ coord_polar(theta="y")”
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6. Examples in R
Extremely easy to overlay different graphical elements and statistical transformations
Very, very many different applications. (Try doing a google search)
Themes can be created and applied to easily create plots with the same ‘look and feel’ (not in my presentation, homework?)
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7. helpful resources
Ggplot2 documentation:
Cookbook;
Presentation by creator of ggplot2, examples and philosophy;
Google, stack overflow, R mailing lists.
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