Aesthetics can be set or mapped within a ggplot
call.
- An aesthetic defined within
aes(...)
is mapped from the data, and a legend created.
- An aesthetic may also be set to a single value, by defining it outside
aes()
.
In this case, it appears you wish to set alpha = 0.8
and map colour = group
.
To do this,
Place the alpha = 0.8
outside the aes()
definition.
g <- ggplot(df, aes(x = x, y = y, group = group))
g <- g + geom_line(aes(colour = group))
g <- g + geom_point(aes(colour = group), alpha = 0.8)
g
For any mapped variable you can supress the appearance of a legend by using guide = 'none'
in the appropriate scale_...
call. eg.
g2 <- ggplot(df, aes(x = x, y = y, group = group)) +
geom_line(aes(colour = group)) +
geom_point(aes(colour = group, alpha = 0.8))
g2 + scale_alpha(guide = 'none')
Which will return an identical plot
EDIT
@Joran's comment is spot-on, I've made my answer more comprehensive
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