| symbols {graphics} | R Documentation |
This function draws symbols on a plot. One of six symbols; circles, squares, rectangles, stars, thermometers, and boxplots, can be plotted at a specified set of x and y coordinates. Specific aspects of the symbols, such as relative size, can be customized by additional parameters.
symbols(x, y = NULL, circles, squares, rectangles, stars,
thermometers, boxplots, inches = TRUE, add = FALSE,
fg = par("col"), bg = NA, xlab = NULL, ylab = NULL, main = NULL,
xlim = NULL, ylim = NULL, ...)
x, y |
the x and y co-ordinates for the centres of the symbols.
They can be specified in any way which is accepted by
xy.coords. |
circles |
a vector giving the radii of the circles. |
squares |
a vector giving the length of the sides of the squares. |
rectangles |
a matrix with two columns. The first column gives widths and the second the heights of rectangles. |
stars |
a matrix with three or more columns giving the lengths
of the rays from the center of the stars. NA values
are replaced by zeroes. |
thermometers |
a matrix with three or four columns. The first
two columns give the width and height of the thermometer symbols. If
there are three columns, the third is taken as a proportion: the
thermometers are filled (using colour fg) from their base to
this proportion of their height. If there are four columns, the
third and fourth columns are taken as proportions and the
thermometers are filled between these two proportions of their
heights. The part of the box not filled in fg will be filled
in the background colour (default transparent) given by bg. |
boxplots |
a matrix with five columns. The first two columns give the width and height of the boxes, the next two columns give the lengths of the lower and upper whiskers and the fifth the proportion (with a warning if not in [0,1]) of the way up the box that the median line is drawn. |
inches |
TRUE, FALSE or a positive number.
See Details. |
add |
if add is TRUE, the symbols are added to
an existing plot, otherwise a new plot is created. |
fg |
colour(s) the symbols are to be drawn in. |
bg |
if specified, the symbols are filled with colour(s), the
vector bg being recycled to the number of symbols.
The default is to leave the symbols unfilled. |
xlab |
the x label of the plot if add is not true.
Defaults to the deparsed expression used for x. |
ylab |
the y label of the plot. Unused if add = TRUE. |
main |
a main title for the plot. Unused if add = TRUE. |
xlim |
numeric vector of length 2 giving the x limits for the
plot. Unused if add = TRUE. |
ylim |
numeric vector of length 2 giving the y limits for the
plot. Unused if add = TRUE. |
... |
graphics parameters can also be passed to this function,
as can the plot aspect ratio asp (see plot.window). |
Observations which have missing coordinates or missing size
parameters are not plotted. The exception to this is stars.
In that case, the length of any ray which is NA is reset
to zero.
Argument inches controls the sizes of the symbols. If
TRUE (the default), the symbols are scaled so that the
largest dimension of any symbol is one inch. If a positive number is
given the symbols are scaled to make largest dimension this size in
inches (so TRUE and 1 are equivalent). If inches
is FALSE, the units are taken to be those of the appropriate
axes. (For circles, squares and stars the units of the x axis are
used. For boxplots, the lengths of the whiskers are regarded as
dimensions alongside width and height when scaling by inches,
and are otherwise interpreted in the units of the y axis.)
Circles of radius zero are plotted at radius one pixel (which is
device-dependent).
On windows devices circles are plotted
at radius at least one pixel as some Windows versions omit smaller
circles.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
W. S. Cleveland (1985) The Elements of Graphing Data. Monterey, California: Wadsworth.
Murrell, P. (2005) R Graphics. Chapman & Hall/CRC Press.
stars for drawing stars with a bit more
flexibility. If are about doing “bubble plots” by
symbols(*,circles=*), you should really consider using
sunflowerplot instead.
x <- 1:10
y <- sort(10*runif(10))
z <- runif(10)
z3 <- cbind(z, 2*runif(10), runif(10))
symbols(x, y, thermometers=cbind(.5, 1, z), inches=.5, fg = 1:10)
symbols(x, y, thermometers = z3, inches=FALSE)
text(x,y, apply(format(round(z3, dig=2)), 1, paste, collapse = ","),
adj = c(-.2,0), cex = .75, col = "purple", xpd=NA)
## Note that example(trees) shows more sensible plots!
N <- nrow(trees)
with(trees, {
## Girth is diameter in inches
symbols(Height, Volume, circles=Girth/24, inches=FALSE,
main="Trees' Girth")# xlab and ylab automatically
## Colours too:
palette(rainbow(N, end = 0.9))
symbols(Height, Volume, circles=Girth/16, inches=FALSE, bg = 1:N,
fg="gray30", main="symbols(*, circles=Girth/16, bg = 1:N)")
palette("default")
})