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", ...)

`x, y` |
coordinate vectors of points to plot. |

`type` |
character indicating the type of plotting; actually any of
the `type` s as in `plot.default` . |

`...` |
Further graphical parameters may also be supplied as arguments. See 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 commonly used are

`pch`

- plotting “character”, i.e., symbol to use. This 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=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.

Values

`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). `col`

- color code or name, see
`par`

. `bg`

- background (“fill”) color for the open plot
symbols given by
`pch=21:25`

. `cex`

- character (or symbol) expansion: a numerical vector.
This works as a multiple of
`par("cex")`

. `lwd`

- line width for drawing symbols see
`par`

.

Others less commonly used are `lty`

and `lwd`

for
types such as `"b"`

and `"l"`

.

Graphical parameters `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.

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
workhorse function `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) }

[Package *graphics* version 2.5.0 Index]