geom_bkde: Display a smooth density estimate.
In ggalt: Extra Coordinate Systems, 'Geoms', Statistical Transformations, Scales and Fonts for 'ggplot2'

Description Usage Arguments Details Aesthetics Computed variables See Also Examples

A kernel density estimate, useful for displaying the distribution of variables with underlying smoothness.

geom_bkde(mapping = NULL, data = NULL, stat = "bkde",
  position = "identity", bandwidth = NULL, range.x = NULL,
  na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...)

stat_bkde(mapping = NULL, data = NULL, geom = "area",
  position = "stack", kernel = "normal", canonical = FALSE,
  bandwidth = NULL, gridsize = 410, range.x = NULL, truncate = TRUE,
  na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...)

`mapping`	Set of aesthetic mappings created by `aes` or `aes_`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
`data`	The data to be displayed in this layer. There are three options: If `NULL`, the default, the data is inherited from the plot data as specified in the call to `ggplot`. A `data.frame`, or other object, will override the plot data. All objects will be fortified to produce a data frame. See `fortify` for which variables will be created. A `function` will be called with a single argument, the plot data. The return value must be a `data.frame.`, and will be used as the layer data.
`position`	Position adjustment, either as a string, or the result of a call to a position adjustment function.
`bandwidth`	the kernel bandwidth smoothing parameter. see `bkde` for details. If `NULL`, it will be computed for you but will most likely not yield optimal results.
`range.x`	vector containing the minimum and maximum values of x at which to compute the estimate. see `bkde` for details
`na.rm`	If `FALSE`, the default, missing values are removed with a warning. If `TRUE`, missing values are silently removed.
`show.legend`	logical. Should this layer be included in the legends? `NA`, the default, includes if any aesthetics are mapped. `FALSE` never includes, and `TRUE` always includes.
`inherit.aes`	If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders`.
`...`	other arguments passed on to `layer`. These are often aesthetics, used to set an aesthetic to a fixed value, like `color = "red"` or `size = 3`. They may also be parameters to the paired geom/stat.
`geom, stat`	Use to override the default connection between `geom_bkde` and `stat_bkde`.
`kernel`	character string which determines the smoothing kernel. see `bkde` for details
`canonical`	logical flag: if TRUE, canonically scaled kernels are used. see `bkde` for details
`gridsize`	the number of equally spaced points at which to estimate the density. see `bkde` for details.
`truncate`	logical flag: if TRUE, data with x values outside the range specified by range.x are ignored. see `bkde` for details

A sample of the output from geom_bkde():

Figure: geombkde01.png

geom_bkde understands the following aesthetics (required aesthetics are in bold):

x
y
alpha
color
fill
linetype
size

density: density estimate
count: density * number of points - useful for stacked density plots
scaled: density estimate, scaled to maximum of 1

See geom_histogram, geom_freqpoly for other methods of displaying continuous distribution. See geom_violin for a compact density display.

data(geyser, package="MASS")

ggplot(geyser, aes(x=duration)) +
  stat_bkde(alpha=1/2)

ggplot(geyser, aes(x=duration)) +
  geom_bkde(alpha=1/2)

ggplot(geyser, aes(x=duration)) +
 stat_bkde(bandwidth=0.25)

ggplot(geyser, aes(x=duration)) +
  geom_bkde(bandwidth=0.25)

Loading required package: ggplot2
Bandwidth not specified. Using '0.14', via KernSmooth::dpik.
Bandwidth not specified. Using '0.14', via KernSmooth::dpik.