[R] Trasparent graphs?

[Thomas W Blackwell]

Kenneth  -

Using base package graphics,  use  plot()  on the first call,
then either  points() or lines()  on subsequent calls to build
up a single plot, layer by layer.  Each call can use an argument
col=... .   However, the colors themselves are not transparent,
AFAIK, so that where two symbols are plotted on top of each other,
only the top layer shows.  If you need to give the appearance of
color mixing, you will have to identify which points coincide,
and plot those again using a third color.  I don't use lattice
graphics, but I presume the situation is much the same.

-  tom blackwell  -  u michigan medical school  -  ann arbor  -

On Tue, 14 Oct 2003, Kenneth Cabrera wrote:

> Hi R-users and R-experts:
>
> Is it posible to make transparent graphics on R?
> I mean, one graphic with colors over another one
> but both visible with transparent options?
>
> Thank you for your help
>
> Kenneth