densCols {grDevices}  R Documentation 
densCols
produces a vector containing colors which encode the
local densities at each point in a scatterplot.
densCols(x, y = NULL, nbin = 128, bandwidth,
colramp = colorRampPalette(blues9[(1:3)]))
blues9
x, y 
the 
nbin 
numeric vector of length one (for both directions) or two
(for x and y separately) specifying the number of equally spaced
grid points for the density estimation; directly used as

bandwidth 
numeric vector (length 1 or 2) of smoothing bandwidth(s).
If missing, a more or less useful default is used. 
colramp 
function accepting an integer 
densCols
computes and returns the set of colors that will be
used in plotting, calling bkde2D(*,
bandwidth, gridsize = nbin, ..)
from package KernSmooth.
blues9
is a set of 9 color shades of blue used as the default in
plotting.
densCols
returns a vector of length nrow(x)
that
contains colors to be used in a subsequent scatterplot. Each color
represents the local density around the corresponding point.
Florian Hahne at FHCRC, originally
bkde2D
from package KernSmooth;
further, smoothScatter()
(package graphics) which
builds on the same computations as densCols
.
x1 < matrix(rnorm(1e3), ncol = 2)
x2 < matrix(rnorm(1e3, mean = 3, sd = 1.5), ncol = 2)
x < rbind(x1, x2)
dcols < densCols(x)
graphics::plot(x, col = dcols, pch = 20, main = "n = 1000")