Formula interface to geom_dotplot()

Scatterplots in ggformula.

Usage

gf_dotplot(
  object = NULL,
  gformula = NULL,
  data = NULL,
  ...,
  alpha,
  color,
  fill,
  group,
  binwidth = NULL,
  binaxis = "x",
  method = "dotdensity",
  binpositions = "bygroup",
  stackdir = "up",
  stackratio = 1,
  dotsize = 1,
  stackgroups = FALSE,
  origin = NULL,
  right = TRUE,
  width = 0.9,
  drop = FALSE,
  xlab,
  ylab,
  title,
  subtitle,
  caption,
  position = "identity",
  show.legend = NA,
  show.help = NULL,
  inherit = TRUE,
  environment = parent.frame()
)

Arguments

object: When chaining, this holds an object produced in the earlier portions of the chain. Most users can safely ignore this argument. See details and examples.
gformula: A formula with shape ~ x. Faceting can be achieved by including | in the formula.
data: A data frame with the variables to be plotted.
...: Additional arguments. Typically these are (a) ggplot2 aesthetics to be set with attribute = value, (b) ggplot2 aesthetics to be mapped with attribute = ~ expression, or (c) attributes of the layer as a whole, which are set with attribute = value.
alpha: Opacity (0 = invisible, 1 = opaque).
color: A color or a formula used for mapping color.
fill: A color for filling, or a formula used for mapping fill.
group: Used for grouping.
binwidth: When method is "dotdensity", this specifies maximum bin width. When method is "histodot", this specifies bin width. Defaults to 1/30 of the range of the data
binaxis: The axis to bin along, "x" (default) or "y"
method: "dotdensity" (default) for dot-density binning, or "histodot" for fixed bin widths (like stat_bin)
binpositions: When method is "dotdensity", "bygroup" (default) determines positions of the bins for each group separately. "all" determines positions of the bins with all the data taken together; this is used for aligning dot stacks across multiple groups.
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 touch. Use smaller values for closer, overlapping dots.
dotsize: The diameter of the dots relative to binwidth, default 1.
stackgroups: should dots be stacked across groups? This has the effect that position = "stack" should have, but can't (because this geom has some odd properties).
origin: When method is "histodot", origin of first bin
right: When method is "histodot", should intervals be closed on the right (a, b], or not [a, b)
width: When binaxis is "y", the spacing of the dot stacks for dodging.
drop: If TRUE, remove all bins with zero counts
xlab: Label for x-axis. See also gf_labs().
ylab: Label for y-axis. See also gf_labs().
title, subtitle, caption: Title, sub-title, and caption for the plot. See also gf_labs().
position: Either a character string naming the position function used for the layer or a position object returned from a call to a position function.
show.legend: A logical indicating whether this layer should be included in the legends. NA, the default, includes layer in the legends if any of the attributes of the layer are mapped.
show.help: If TRUE, display some minimal help.
inherit: A logical indicating whether default attributes are inherited.
environment: An environment in which to look for variables not found in data.

Value

a gg object

Details

There are two basic approaches: dot-density and histodot. 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.

Warning

Dotplots in ggplot2 (and hence in ggformula) often require some fiddling because the default y-axis is meaningless and the ideal size of the dots depends on the aspect ratio of the plot.

Specifying plot attributes

Positional attributes (a.k.a, aesthetics) are specified using the formula in gformula. Setting and mapping of additional attributes can be done through the use of additional arguments. Attributes can be set can be set using arguments of the form attribute = value or mapped using arguments of the form attribute = ~ expression.

In formulas of the form A | B, B will be used to form facets using ggplot2::facet_wrap() or ggplot2::facet_grid(). This provides an alternative to gf_facet_wrap() and gf_facet_grid() that is terser and may feel more familiar to users of lattice.

Evaluation

Evaluation of the ggplot2 code occurs in the environment of gformula. This will typically do the right thing when formulas are created on the fly, but might not be the right thing if formulas created in one environment are used to create plots in another.

References

Wilkinson, L. (1999) Dot plots. The American Statistician, 53(3), 276-281.

Examples

data(penguins, package = "palmerpenguins")
gf_dotplot(~bill_length_mm, fill = ~species, data = penguins)
#> Bin width defaults to 1/30 of the range of the data. Pick better value with
#> `binwidth`.
#> Warning: Removed 2 rows containing missing values or values outside the scale range
#> (`stat_bindot()`).