points {base}

R Documentation

Add Points to a Plot

Description

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.

Usage

points(x, ...)
points.default(x, y=NULL, type="p", pch=par("pch"), col=par("col"),
               bg=NA, cex=1, ...)

Arguments

x, y	coordinate vectors of points to plot.
type	character indicating the type of plotting; actually any of the types as in plot.
pch	plotting “character”, i.e. symbol to use. pch can either be a character or an integer code for a set of graphics symbols. The full set of S symbols is available with pch=0:18, see the last picture from example(points), i.e., the examples below. In addition, there is a special set of R plotting symbols which can be obtained with pch=19:25 and 21:25 can be colored and filled with different colors: pch=19: solid circle, pch=20: bullet (smaller circle), pch=21: circle, pch=22: square, pch=23: diamond, pch=24: triangle point-up, pch=25: triangle point down.
col	color code or name, see colors, palette.
bg	background (“fill”) color for open plot symbols
cex	character expansion
...	Further graphical parameters (see plot.xy and par) may also be supplied as arguments.

Details

The coordinates can be passed in a plotting structure (a list with x and y components), a two-column matrix, a time series, .... See xy.coords.

Graphical parameters are permitted as arguments to this function.

See Also

plot, lines, and the underlying “primitive” plot.xy.

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)

op <- par(bg = "light blue")
x <- seq(0,2*pi, len=51)
## something ``between type="b" and type="o" '' :
plot(x, sin(x), type="o", pch=21, bg=par("bg"), col = "blue", cex=.6,
 main='plot(..., type="o", pch=21, bg=par("bg"))')
par(op)

##-------- Showing all the extra & some char graphics symbols ------------
Pex <- 3 ## good for both .Device=="postscript" and "x11"
ipch <- 1:(np <- 25+11); k <- floor(sqrt(np)); dd <- c(-1,1)/2
rx <- dd + range(ix <- (ipch-1) %/% k)
ry <- dd + range(iy <- 3 + (k-1)-(ipch-1) %% k)
pch <- as.list(ipch)
pch[25+ 1:11] <- as.list(c("*",".", "o","O","0","+","-",":","|","%","#"))
plot(rx, ry, type="n", axes = FALSE, xlab = "", ylab = "",
     main = paste("plot symbols :  points (...  pch = *, cex =", Pex,")"))
abline(v = ix, h = iy, col = "lightgray", lty = "dotted")
for(i in 1:np) {
  pc <- pch[[i]]
  points(ix[i], iy[i], pch = pc, col = "red", bg = "yellow", cex = Pex)
  ## red symbols with a yellow interior (where available)
  text(ix[i] - .3, iy[i], pc, col = "brown", cex = 1.2)
}

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