points {graphics} | R Documentation |
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.
points(x, ...) ## Default S3 method: points(x, y = NULL, type = "p", pch = par("pch"), col = par("col"), bg = NA, cex = 1, ...)
x, y |
coordinate vectors of points to plot. |
type |
character indicating the type of plotting; actually any of
the type s as in plot . |
pch |
plotting “character”, i.e., symbol to use. pch can
either be a single character or an integer code for one of 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=26:32 are currently unused, and pch=32:255
give the text symbol in a single-byte locale. In a multi-byte locale
such as UTF-8, numeric values of pch greater than or equal to
32 specify a Unicode code point (except for the symbol font as
selected by par(font = 5) ).
If pch is an integer or character NA or an empty
character string, the point is omitted from the plot.
Value pch="." is handled specially. It is a rectangle of
side 0.01 inch (scaled by cex ). In addition, if cex =
1 (the default), each side is at least one pixel (1/72 inch on
the pdf , postscript and
xfig devices). The details here have been changed
for 2.1.0 and are subject to change.
|
col |
color code or name, see par . |
bg |
background (“fill”) color for open plot symbols given by
pch=21:25 . |
cex |
character (or symbol) expansion: a numerical vector.
This works as a multiple of par("cex") . |
... |
Further graphical parameters (see plot.xy
and par ) may also be supplied as arguments. |
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
.
Arguments pch
, col
, bg
, cex
and lwd
can be vectors (which will be recycled as needed) giving a value for each
point plotted. If lines are to be plotted (e.g. for
type = "b"
the first element of lwd
is used.
Points whose x
, y
, pch
, col
or cex
value is NA
are omitted from the plot.
Graphical parameters are permitted as arguments to this function.
What is meant by ‘a single character’ is locale-dependent.
The encoding may not have symbols for some or all of the characters in
pch=128:255
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
plot
, lines
, and the underlying
“primitive” plot.xy
.
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 <- 0:35; np <- length(ipch); k <- floor(sqrt(np)); dd <- c(-1,1)/2 rx <- dd + range(ix <- ipch %/% k) ry <- dd + range(iy <- 3 + (k-1)- ipch %% k) pch <- as.list(ipch) pch[26+ 1:10] <- 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) }