axis(which, at, labels=TRUE, lty="solid",
col=par("fg"), cex=1)
which
| an integer specifying which side of the plot the axis is to be drawn on. |
at
| the points at which tick-marks are to be drawn. |
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. |
lty
| the line texture to be used for the axis. |
col
| the color for the axis labels. |
cex
| the expansion factor for the axis labels. |
axis adds an axis to an already existing plot.
The axis is placed as follows:
1=below, 2=left, 3=above and 4=right.