geom_dotplot {ggplot2} | R Documentation |
In a dot plot, the width of a dot corresponds to the bin width (or maximum width, depending on the binning algorithm), and dots are stacked, with each dot representing one observation.
geom_dotplot(mapping = NULL, data = NULL, stat = "bindot", position = "identity", na.rm = FALSE, binwidth = NULL, binaxis = "x", method = "dotdensity", binpositions = "bygroup", stackdir = "up", stackratio = 1, dotsize = 1, stackgroups = FALSE, ...)
binaxis |
which axis to bin along "x" (default) or "y" |
method |
"dotdensity" (default) for dot-density binning, or "histodot" for fixed bin widths (like stat_bin) |
binwidth |
When |
binpositions |
When |
stackdir |
which direction to stack the dots. "up" (default), "down", "center", "centerwhole" (centered, but with dots aligned) |
stackratio |
how close to stack the dots. Default is 1, where dots just just touch. Use smaller values for closer, overlapping dots. |
dotsize |
The diameter of the dots relative to
|
stackgroups |
should dots be stacked across groups?
This has the effect that |
mapping |
The aesthetic mapping, usually constructed
with |
data |
A layer specific dataset - only needed if you want to override the plot defaults. |
stat |
The statistical transformation to use on the data for this layer. |
position |
The position adjustment to use for overlappling points on this layer |
na.rm |
If |
... |
other arguments passed on to
|
With dot-density binning, the bin positions are
determined by the data and binwidth
, which is the
maximum width of each bin. See Wilkinson (1999) for
details on the dot-density binning algorithm.
With histodot binning, the bins have fixed positions and fixed widths, much like a histogram.
When binning along the x axis and stacking along the y axis, the numbers on y axis are not meaningful, due to technical limitations of ggplot2. You can hide the y axis, as in one of the examples, or manually scale it to match the number of dots.
geom_dotplot
understands the following aesthetics (required aesthetics are in bold):
x
y
alpha
colour
fill
Wilkinson, L. (1999) Dot plots. The American Statistician, 53(3), 276-281.
ggplot(mtcars, aes(x = mpg)) + geom_dotplot() ggplot(mtcars, aes(x = mpg)) + geom_dotplot(binwidth = 1.5) # Use fixed-width bins ggplot(mtcars, aes(x = mpg)) + geom_dotplot(method="histodot", binwidth = 1.5) # Some other stacking methods ggplot(mtcars, aes(x = mpg)) + geom_dotplot(binwidth = 1.5, stackdir = "center") ggplot(mtcars, aes(x = mpg)) + geom_dotplot(binwidth = 1.5, stackdir = "centerwhole") # y axis isn't really meaningful, so hide it ggplot(mtcars, aes(x = mpg)) + geom_dotplot(binwidth = 1.5) + scale_y_continuous(name = "", breaks = NA) # Overlap dots vertically ggplot(mtcars, aes(x = mpg)) + geom_dotplot(binwidth = 1.5, stackratio = .7) # Expand dot diameter ggplot(mtcars, aes(x =mpg)) + geom_dotplot(binwidth = 1.5, dotsize = 1.25) # Examples with stacking along y axis instead of x ggplot(mtcars, aes(x = 1, y = mpg)) + geom_dotplot(binaxis = "y", stackdir = "center") ggplot(mtcars, aes(x = factor(cyl), y = mpg)) + geom_dotplot(binaxis = "y", stackdir = "center") ggplot(mtcars, aes(x = factor(cyl), y = mpg)) + geom_dotplot(binaxis = "y", stackdir = "centerwhole") ggplot(mtcars, aes(x = factor(vs), fill = factor(cyl), y = mpg)) + geom_dotplot(binaxis = "y", stackdir = "center", position = "dodge") # binpositions="all" ensures that the bins are aligned between groups ggplot(mtcars, aes(x = factor(am), y = mpg)) + geom_dotplot(binaxis = "y", stackdir = "center", binpositions="all") # Stacking multiple groups, with different fill ggplot(mtcars, aes(x = mpg, fill = factor(cyl))) + geom_dotplot(stackgroups = TRUE, binwidth = 1, binpositions = "all") ggplot(mtcars, aes(x = mpg, fill = factor(cyl))) + geom_dotplot(stackgroups = TRUE, binwidth = 1, method = "histodot") ggplot(mtcars, aes(x = 1, y = mpg, fill = factor(cyl))) + geom_dotplot(binaxis = "y", stackgroups = TRUE, binwidth = 1, method = "histodot")