| axis {base} | R Documentation |
Add an Axis to a Plot
Description
Adds an axis to the current plot, allowing the specification of the side, position, labels, and other options.
Usage
axis(side, at = NULL, labels = TRUE, tick = TRUE, line = 0,
pos = NA, outer = FALSE, font = NA, vfont = NULL,
lty = "solid", lwd = 1, col = NULL, ...)
Arguments
side |
an integer specifying which side of the plot the axis is to be drawn on. The axis is placed as follows: 1=below, 2=left, 3=above and 4=right. |
at |
the points at which tick-marks are to be drawn. Non-finite
(infinite, |
labels |
this can either be a logical value specifying whether (numerical) annotations are to be made at the tickmarks, or a vector of character strings to be placed at the tickpoints. |
tick |
a logical value specifying whether tickmarks should be drawn |
.
line |
the number of lines into the margin which the axis will
be drawn. This overrides the value of the graphical parameter
|
pos |
the coordinate at which the axis line is to be drawn.
this overrides the value of both |
outer |
a logical value indicating whether the axis should be drawn in the outer plot margin, rather than the standard plot margin. |
font |
font for text. |
vfont |
vector font for text. |
lty, lwd |
line type, width for the axis line and the tick marks. |
col |
color for the axis line and the tick marks. The default
|
... |
other graphical parameters may also be passed as arguments to
this function, e.g., |
Details
The axis line is drawn from the lowest to the highest value of
at, but will be clipped at the plot region. Only ticks which
are drawn from points within the plot region (up to a tolerance for
rounding error) are plotted, but the ticks and their labels may well
extend outside the plot region.
When at = NULL, pretty tick mark locations are computed internally,
from par("usr","lab"), and par("xlog") (or
ylog respectively).
Value
This function is invoked for its side effect, which is to add an axis to an already existing plot.
Examples
plot(1:4, rnorm(4), axes=FALSE)
axis(1, 1:4, LETTERS[1:4])
axis(2)
box() #- to make it look "as usual"
plot(1:7, rnorm(7), main = "axis() examples",
type = "s", xaxt="n", frame = FALSE, col = "red")
axis(1, 1:7, LETTERS[1:7], col.axis = "blue")
# unusual options:
axis(4, col = "violet", col.axis="dark violet",lwd = 2)
axis(3, col = "gold", lty = 2, lwd = 0.5)