The R Project SVN R

\name{points}
\title{Add Points to a Plot}
\usage{
points(x, y, pch="o", \dots)
points.default(x, y=NULL, pch=1, col="black", \dots)
}
\alias{points}
\alias{points.default}
\arguments{
\item{x, y}{coordinate vectors of points to plot.}
\item{pch}{plotting 'character', i.e. symbol to use.  \code{pch} can
either be a \code{\link{character}} or an integer code for a set of
graphics symbols.  The full set of S symbols is available with \code{pch=0:18}.

In addition, there is a special set of R plotting symbols which
can be obtained with \code{pch=19:25} and can be colored and filled
with different colors:
\code{pch=19}: solid circle,
\code{pch=20}: bullet,
\code{pch=21}: circle,
\code{pch=22}: square,
\code{pch=23}: diamond,
\code{pch=24}: triangle point-up,
\code{pch=25}: triangle point down.}
\item{col}{color to use.}
\item{\dots}{Further graphical parameters (see \code{\link{par}}) may
also be supplied as arguments.}
}
\description{
\code{points} is a generic function to draw a sequence of points at the
specified coordinates. 
The specified character(s) are plotted, centered at the coordinates.

Graphical parameters are permitted as arguments to this function.
}
\seealso{
\code{\link{plot}}, \code{\link{lines}}.
}   
\examples{
plot(-4:4, -4:4, type = 'n')# setting up coord. system
points(rnorm(200), rnorm(200), col = 'red')
points(rnorm(100)/2, rnorm(100)/2, col = 'blue', cex = 1.5)

## Showing all the graphics symbols
ipch <- 1:25
iy <- 3 + 4-(ipch-1) \%\% 5
ix <- (ipch-1) \%/\% 5
plot(ix, iy, type='n', axes = F, xlab = '', ylab = '',
     main = 'plot symbols :  points (..  pch = * )')
abline(v=ix, h=iy, col = "lightgray", lty = "dotted")
for(i in ipch) { # red symbols with a yellow interior (where available)
  points(ix[i],      iy[i], pch=i, col="red", bg="yellow", cex = 15)
  text  (ix[i] - .3, iy[i], i, col="brown", cex = 1.5)
}
}
\keyword{aplot}