This is a special type of (scatter)plot, with points being arranged only on the
horizontal axis (it has no vertical axis). Useful when inspecting if points
are grouped into naturally occuring clusters, mainly for crisp calibration purposes.
The argument ...
is used to pass arguments to the various graphical
parameters from ?par
, and also to the settings from ?jitter
.
The points have a default cex
(character expansion) value of 1, and
a default pch
value of 1 (empty points), which can be modified
accordingly (for instance value 21 for filled points). When pch = 21
,
the color for the margins of the points can be specified via the argument
col
, while the argument bg
will determine the fill color
of the points.
The axis labels have a default cex.axis
value of 0.8, which affects
both the tickmarks labels and the axis labels.
When jittering the points, default values of 0.5 are used for the parameters
factor
and amount
, on the horizontal axis. More details
can be found in the base function jitter()
.
Although the points are displayed in a single dimension, on the horizontal axis,
the R graphical window will still have the default squared shape, with a lot of
empty space on the vertical axis. Users are free to create their custom code to
determine the size of the graphics window, or simply resize it to a suitable
height.