Alpha-transparency scales are not tremendously useful, but can be a
convenient way to visually down-weight less important observations.
scale_alpha()
is an alias for scale_alpha_continuous()
since
that is the most common use of alpha, and it saves a bit of typing.
Arguments
- ...
Other arguments passed on to
continuous_scale()
,binned_scale()
, ordiscrete_scale()
as appropriate, to control name, limits, breaks, labels and so forth.- range
Output range of alpha values. Must lie between 0 and 1.
See also
The documentation on colour aesthetics.
Other alpha scales: scale_alpha_manual()
, scale_alpha_identity()
.
Other colour scales:
scale_colour_brewer()
,
scale_colour_continuous()
,
scale_colour_gradient()
,
scale_colour_grey()
,
scale_colour_hue()
,
scale_colour_identity()
,
scale_colour_manual()
,
scale_colour_steps()
,
scale_colour_viridis_d()
Examples
p <- ggplot(mpg, aes(displ, hwy)) +
geom_point(aes(alpha = year))
p
p + scale_alpha("cylinders")
p + scale_alpha(range = c(0.4, 0.8))