geom_dotplot() with median line

## Settings for RMarkdown http://yihui.name/knitr/options#chunk_options
opts_chunk$set(comment = "", warning = FALSE, message = FALSE, echo = TRUE, 
    tidy = FALSE, fig.width = 7, fig.height = 7)
options(width = 116, scipen = 10)

References

• http://had.co.nz/ggplot2/docs/geom_dotplot.html
• http://stackoverflow.com/questions/11889353/avoiding-overlap-when-jittering-points

Simple plots. See changes due to different binwidth.

library(ggplot2)

ggplot(data = iris) +
    geom_dotplot(aes(y = Sepal.Length, x = Species, fill = Species),
                 binaxis = "y",         # which axis to bin along
                 binwidth = 0.05,       # Minimal difference considered diffeerent
                 stackdir = "center"    # Centered
                 )

ggplot(data = iris) +
    geom_dotplot(aes(y = Sepal.Length, x = Species, fill = Species),
                 binaxis = "y",         # which axis to bin along
                 binwidth = 0.1,        # Minimal difference considered diffeerent
                 stackdir = "center"    # Centered
                 )

ggplot(data = iris) +
    geom_dotplot(aes(y = Sepal.Length, x = Species, fill = Species),
                 binaxis = "y",         # which axis to bin along
                 binwidth = 0.2,        # Minimal difference considered diffeerent
                 stackdir = "center"    # Centered
                 )

Additing median line

ggplot(data = iris, aes(y = Sepal.Length, x = Species)) + # Move y and x here so than they can be used in stat_*
    geom_dotplot(aes(fill = Species),   # Use fill = Species here not in ggplot()
                 binaxis = "y",         # which axis to bin along
                 binwidth = 0.1,        # Minimal difference considered diffeerent
                 stackdir = "center"    # Centered
                 ) +
    stat_summary(fun.y = median, fun.ymin = median, fun.ymax = median,
                 geom = "crossbar", width = 0.5)