4.1 Grammar

  • Grammar answers question: What is a statistical graphic?
  • “The Grammar of Graphics” (Wilkinson 2013)20
  • “A Layered Grammar of Graphics” (Wickham 2010b)21
  • Good grammar (Wickham 2010b, 3)
    • provides insights into the composition of complicated graphics
    • reveals unexpected connections between seemingly different graphics
    • is just the first step in creating a good sentence
  • Grammar tells us that (Wickham 2016)
    • a statistical graphic is a mapping from data to aesthetic attributes (color, shape, size) of geometric objects (points, lines, bars)
    • Plot may contain statistical transformations/is drawn on specific coordinate system
    • Faceting used to generate the same plot for different subsets of the dataset.
    • Combination of these independent components that make up a graphic
  • Possibility of grammatically correct but nonsensical graph
  • Grammar = conceptually useful even if you don’t use Ggplot2 (e.g., if you use Plotly)

References

Wickham, Hadley. 2010b. “A Layered Grammar of Graphics.” J. Comput. Graph. Stat. 19 (1): 3–28.

Wickham, Hadley. 2016. Ggplot2: Elegant Graphics for Data Analysis. Springer.

Wilkinson, Leland. 2013. The Grammar of Graphics. Springer Science & Business Media.

  1. Objective: Describe all features underlying statistical graphs↩

  2. Focuses on the primacy of layers and adapts it for R↩