ggplot2

ggplot2 is a plotting system for R, based on the grammar of graphics, which tries to take the good parts of base and lattice graphics and none of the bad parts. It takes care of many of the fiddly details that make plotting a hassle (like drawing legends) as well as providing a powerful model of graphics that makes it easy to produce complex multi-layered graphics.

A copy of this site for local use is available here, as a 6 meg zip file. To use it, unzip and open the index.html page.

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Mailing list

You are welcome to ask ggplot2 questions on R-help, but if you'd like to participate in a more focussed mailing list, please sign up for the ggplot2 mailing list:

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You must be a member to post messages, but anyone can read the archived discussions.

Installation

install.packages("ggplot2")

(you'll need to make sure you have the most recent version of R to get the most recent version of ggplot)

ggplot book

ggplot2: Elegant Graphics for Data Analysis is now available on amazon.com. It describes the theoretical underpinnings of ggplot2 and shows you how all the pieces fit together. The book gives you an high-level overview of the package that you just can't get from reading the documentation.

You can read sample chapters and download the book code from the book website.

Other resources

You might also find the following presentations useful:

• ggplot2: past, present and future.
• One hour ggplot2 workshop given at Vanderbilt, 2007. (r code)

Training

From time-to-time I offer face-to-face workshops and training seminars. You can see upcoming events at lookingatdata.com.

Reference manual

Geoms

Geoms, short for geometric objects, describe the type of plot you will produce. Read more

• geom_abline
  Line, specified by slope and intercept
• geom_bar
  Bars, rectangles with bases on y-axis
• geom_blank
  Blank, draws nothing
• geom_contour
  Display contours of a 3d surface in 2d
• geom_density
  Display a smooth density estimate
• geom_errorbar
  Error bars
• geom_freqpoly
  Frequency polygon
• geom_histogram
  Histogram
• geom_jitter
  Points, jittered to reduce overplotting
• geom_linerange
  An interval represented by a vertical line
• geom_point
  Points, as for a scatterplot
• geom_polygon
  Polygon, a filled path
• geom_rect
  2d rectangles
• geom_rug
  Marginal rug plots
• geom_smooth
  Add a smoothed condition mean.
• geom_text
  Textual annotations
• geom_vline
  Line, vertical

• geom_area
  Area plots
• geom_bin2d
  Add heatmap of 2d bin counts
• geom_boxplot
  Box and whiskers plot
• geom_crossbar
  Hollow bar with middle indicated by horizontal line
• geom_density2d
  Contours from a 2d density estimate
• geom_errorbarh
  Horizontal error bars
• geom_hex
  Tile the plane with hexagons
• geom_hline
  Line, horizontal
• geom_line
  Connect observations, in ordered by x value
• geom_path
  Connect observations, in original order
• geom_pointrange
  An interval represented by a vertical line, with a point in the middle
• geom_quantile
  Add quantile lines from a quantile regression
• geom_ribbon
  Ribbons, y range with continuous x values
• geom_segment
  Single line segments
• geom_step
  Connect observations by stairs
• geom_tile
  Tile plot as densely as possible, assuming that every tile is the same size.

Statistics

It's often useful to transform your data before plotting, and that's what statistical transformations do. Read more

• stat_abline
  Add a line with slope and intercept
• stat_bin2d
  Bin 2d plane into rectangles
• stat_boxplot
  Calculate components of box and whisker plot
• stat_density
  Density estimation, 1D
• stat_function
  Superimpose a function
• stat_identity
  Don't transform data
• stat_quantile
  Continuous quantiles
• stat_spoke
  Convert angle and radius to xend and yend
• stat_summary
  Summarise y values at every unique x
• stat_vline
  Add a vertical line

• stat_bin
  Bin data
• stat_binhex
  Bin 2d plane into hexagons
• stat_contour
  Contours of 3d data
• stat_density2d
  Density estimation, 2D
• stat_hline
  Add a horizontal line
• stat_qq
  Calculation for quantile-quantile plot
• stat_smooth
  Add a smoother
• stat_sum
  Sum unique values. Useful for overplotting on scatterplots
• stat_unique
  Remove duplicates

Scales

Scales control the mapping between data and aesthetics. Read more

• scale_alpha
  Alpha scale for continuous variable
• scale_continuous
  Continuous position scale
• scale_datetime
  Position scale, date time
• scale_gradient
  Smooth gradient between two colours
• scale_gradientn
  Smooth gradient between n colours
• scale_hue
  Qualitative colour scale with evenly spaced hues
• scale_linetype
  Scale for line patterns
• scale_shape
  Scale for shapes, aka glyphs

• scale_brewer
  Sequential, diverging and qualitative colour scales from colorbrewer.org
• scale_date
  Position scale, date
• scale_discrete
  Discrete position scale
• scale_gradient2
  Smooth gradient between three colours (high, low and midpoints)
• scale_grey
  Sequential grey colour scale
• scale_identity
  Use values without scaling
• scale_manual
  Create your own discrete scale
• scale_size
  Size scale for continuous variable

Coordinate systems

Coordinate systems adjust the mapping from coordinates to the 2d plane of the computer screen. Read more

• coord_cartesian
  Cartesian coordinates
• coord_flip
  Flipped cartesian coordinates
• coord_polar
  Polar coordinates

• coord_equal
  Equal scale cartesian coordinates
• coord_map
  Map projections
• coord_trans
  Transformed cartesian coordinate system

Faceting

Facets display subsets of the dataset in different panels. Read more

• facet_grid
  Lay out panels in a rectangular/tabular manner.

• facet_wrap
  Wrap a 1d ribbon of panels into 2d.

Position adjustments

Position adjustments can be used to fine tune positioning of objects to achieve effects like dodging, jittering and stacking. Read more

• position_dodge
  Adjust position by dodging overlaps to the side
• position_identity
  Don't adjust position
• position_stack
  Stack overlapping objects on top of one another

• position_fill
  Stack overlapping objects on top of one another, and standardise have equal height
• position_jitter
  Jitter points to avoid overplotting

© Hadley Wickham 2010