stat_density {ggplot2} | R Documentation |
Density estimation, 1D
stat_density(mapping=NULL, data=NULL, geom="area", position="stack", adjust=1, kernel="gaussian", trim=FALSE, na.rm=FALSE, ...)
mapping |
mapping between variables and aesthetics generated by aes |
data |
dataset used in this layer, if not specified uses plot dataset |
geom |
geometric used by this layer |
position |
position adjustment used by this layer |
adjust |
see ?density for details |
kernel |
kernel used for density estimation, see density for details |
trim |
NULL |
na.rm |
NULL |
... |
other arguments |
This page describes stat_density, see layer
and qplot
for how to create a complete plot from individual components.
A layer
The following aesthetics can be used with stat_density. Aesthetics are mapped to variables in the data with the aes
function: stat\_density(\code{aes}(x = var))
x
: x position (required)
y
: y position
fill
: internal colour
Hadley Wickham, http://had.co.nz/
stat_bin
: for the histogram
density
: for details of the algorithm used
## Not run: m <- ggplot(movies, aes(x=rating)) m + geom_density() # Adjust parameters m + geom_density(kernel = "rectangular") m + geom_density(kernel = "biweight") m + geom_density(kernel = "epanechnikov") m + geom_density(adjust=1/5) # Very rough m + geom_density(adjust=5) # Very smooth # Adjust aesthetics m + geom_density(aes(fill=factor(Drama)), size=2) # Scale so peaks have same height: m + geom_density(aes(fill=factor(Drama), y = ..scaled..), size=2) m + geom_density(colour="darkgreen", size=2) m + geom_density(colour="darkgreen", size=2, fill=NA) m + geom_density(colour="darkgreen", size=2, fill="green") # Change scales (m <- ggplot(movies, aes(x=votes)) + geom_density(trim = TRUE)) m + scale_x_log10() m + coord_trans(x="log10") m + scale_x_log10() + coord_trans(x="log10") # Also useful with m + stat_bin() # Make a volcano plot ggplot(diamonds, aes(x = price)) + geom_density(aes(min = -..density.., adjust= 0.5),fill="grey50", colour=NA) + facet_grid(. ~ cut) + coord_flip() # Stacked density plots # If you want to create a stacked density plot, you need to use # the 'count' (density * n) variable instead of the default density # Loses marginal densities qplot(rating, ..density.., data=movies, geom="density", fill=mpaa, position="stack") # Preserves marginal densities qplot(rating, ..count.., data=movies, geom="density", fill=mpaa, position="stack") # You can use position="fill" to produce a conditional density estimate qplot(rating, ..count.., data=movies, geom="density", fill=mpaa, position="fill") # Need to be careful with weighted data m <- ggplot(movies, aes(x=rating, weight=votes)) m + geom_histogram(aes(y = ..count..)) + geom_density(fill=NA) m <- ggplot(movies, aes(x=rating, weight=votes/sum(votes))) m + geom_histogram(aes(y=..density..)) + geom_density(fill=NA, colour="black") movies$decade <- round_any(movies$year, 10) m <- ggplot(movies, aes(x=rating, colour=decade, group=decade)) m + geom_density(fill=NA) m + geom_density(fill=NA) + aes(y = ..count..) # Use qplot instead qplot(length, data=movies, geom="density", weight=rating) qplot(length, data=movies, geom="density", weight=rating/sum(rating)) ## End(Not run)