`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 `x`

and `y`

arguments provide the x and y
coordinates of the points. Any reasonable way of defining the
coordinates is acceptable. See the function `xy.coords`

for details. If supplied separately, they must be of the same length.

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
`gridsize`

in `bkde2D()`

.

bandwidth

numeric vector (length 1 or 2) of smoothing bandwidth(s).
If missing, a more or less useful default is used. `bandwidth`

is subsequently passed to function `bkde2D`

.

colramp

function accepting an integer `n`

as an argument and
returning `n`

colors.

`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.

`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.

`bkde2D`

from package KernSmooth;
further, `smoothScatter()`

(package graphics) which
builds on the same computations as `densCols`

.

# NOT RUN { 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") # }