gg2density: Grob function: 2d density

In hadley/ggplot1: Before there was ggplot2

Grob function: 2d density

Description

Perform a 2D kernel density estimatation using kde2d and display the results with contours.

Usage

gg2density(plot, aesthetics = list(), ..., data = NULL)

Arguments

plot	the plot object to modify
aesthetics	named list of aesthetic mappings, see details for more information
...	other options, see details for more information
data	data source, if not specified the plot default will be used

Details

This is another function useful for dealing with overplotting.

Aesthetic mappings that this grob function understands:

• x:x position (required)

• y:y position (required)

These can be specified in the plot defaults (see ggplot) or in the aesthetics argument. If you want to modify the position of the points or any axis options, you will need to add a position scale to the plot. These functions start with ps, eg. pscontinuous or pscategorical

Other options:

• passed to ggcontour, see it for details

See Also

ggcontour for another way of dealing with over plotting

Examples

library(ggplot2movies)
m <- ggpoint(ggplot(movies, aesthetics=list(y=length, x=rating)))
dens <- MASS::kde2d(movies$rating, movies$length)
densdf <- data.frame(expand.grid(rating = dens$x, length = dens$y), z=as.vector(dens$z))
ggcontour(m, list(z=z), data=densdf)
gg2density(m)
# they don't look the same due to scaling effects on kde2d

hadley/ggplot1 documentation built on Dec. 1, 2024, 11:23 a.m.