ggplot2

Elaine McVeyBD Technologies

Triangle Area R useRs Group

September 29, 2010

What is ggplot2?

ggplot2 is an R package written by Hadley Wickham that provides a comprehensive framework for statistical graphics based on The Grammar of Graphics (LeLand Wilkinson, 2005)

Goal

To show you enough about ggplot2 that you can understand its capabilities, get started using it, and know where to learn more.

Benefits

• Since ggplot2 has an underlying conceptual framework, it becomes very powerful once you understand it.

• ggplot2 code is concise and readable• Writing statistical functions (i.e. panel functions) for

ggplot2 is relatively easy.• ggplot2 enforces the link between the data and the

legend, so labeling errors are minimized.• The layering concept makes it easy to combine data

from different dataframes in a single plot.• The active user community provides a good place to get

help and drives ongoing development.

Jumping In - Dataframe

Jumping In – First Plot

Layers

More Layers - oops

More Layers - corrected

Non-Mapped Attributes

Accidental Aesthetic Mapping

Aesthetic Mapping by geom

Bigger Dataframe

Facets and Colors

Statistical Summaries

Creating errBars

Lattice Comparison

Expanding errBars

Layering Dataframes

plyr aside:

Layering Dataframes in geoms

Updating Plots

Where to go next

1) ggplot2: Elegant Graphics for Data Analysis(skip qplot)

2) had.co.nz/ggplot2 (& plyr & reshape . . . )

3) Google group listserv

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