2-D Generalization of Boxplot

If bin is an eroded hexbin object, i.e., an erodebin object, hboxplot() plots the high counts cells selected by erode(). By default, the high counts cells contain 50 percent of the counts so analagous to the interquartile “range”. The function distinguishes the last cells eroded using color. These cells correspond to one definition of the bivariate median.

hboxplot(bin, xbnds = NULL, ybnds = NULL,
         density, border = c(0, grey(0.7)), pen = c(2, 3),
         unzoom = 1.1, clip ="off", reshape = FALSE,
         xlab = NULL, ylab = NULL, main = "")

Arguments

bin

an object of class hexbin.

xbnds,ybnds

global x- and y-axis plotting limits for multiple plots.

density, border

arguments for polygon() each of length two, the first for the median, the second for the other cells.

pen

colors (“pen numbers”) for polygon().

unzoom

plot limit expansion factor when xbnds is missing.

clip

either 'on' or 'off' are the allowed arguments, when on everything is clipped to the plotting region.

reshape

logical value to reshape the plot although xbnds and ybnds are present.

xlab, ylab, main

x- and y- axis labels and main title

Value

invisibly, the hexViewport() used internally. Used to add to the plot afterwards.

References

see in grid.hexagons.

Details

The density, border, and pen arguments correspond to the polygon function calls for plotting two types of cells. The cell types, pen numbers and suggested colors are

TYPE	PEN	COLOR
cells of bin	2	light gray
last eroded cells of bin (median cells)	1	black

The erode components of the hexbin objects must be present for the medians cells to plot.

When xbnds is missing or reshape is true, the plot changes graphics parameters and resets them. When xbnds is missing the function also zooms in based on the available data to provide increased resolution.

The zoom used the hexagon cell centers. The unzoom argument backs off a bit so the whole hexagon will fit in the plot.

Hboxplot() is used as a stand alone function, for producing separate legends .....

See also

hexbin, erode, hcell2xy, gplot.hexbin, grid.hexagons, grid.hexlegend

Examples

set.seed(753)
##  boxplot of smoothed counts
x <- rnorm(10000)
y <- rnorm(10000)

bin <- hexbin(x,y)
erodebin <- erode(smooth.hexbin(bin))

hboxplot(erodebin)

hboxplot(erodebin, density = c(32,7), border = c(2,4))

hp <- hboxplot(erodebin, density = c(-1,17),
               main = "hboxplot(erode*(smooth*(.)))")
pushHexport(hp)
library("grid")
grid.points(x[1:10], y[1:10])# just non-sense to show the principle
popViewport()