This function is used in conjunction with a position scale to create a secondary axis, positioned opposite of the primary axis. All secondary axes must be based on a one-to-one transformation of the primary axes.
sec_axis(trans = NULL, name = waiver(), breaks = waiver(), labels = waiver()) dup_axis(trans = ~., name = derive(), breaks = derive(), labels = derive()) derive()
A transformation formula
The name of the secondary axis
NULL for no breaks
waiver() for the default breaks computed by the transformation object
A numeric vector of positions
A function that takes the limits as input and returns breaks as output
NULL for no labels
waiver() for the default labels computed by the transformation object
A character vector giving labels (must be same length as
A function that takes the breaks as input and returns labels as output
sec_axis is used to create the specifications for a secondary axis.
Except for the
trans argument any of the arguments can be set to
derive() which would result in the secondary axis inheriting the
settings from the primary axis.
dup_axis is provide as a shorthand for creating a secondary axis that
is a duplication of the primary axis, effectively mirroring the primary axis.
p <- ggplot(mtcars, aes(cyl, mpg)) + geom_point() # Create a simple secondary axis p + scale_y_continuous(sec.axis = sec_axis(~.+10))# Inherit the name from the primary axis p + scale_y_continuous("Miles/gallon", sec.axis = sec_axis(~.+10, name = derive()))# Duplicate the primary axis p + scale_y_continuous(sec.axis = dup_axis())# You can pass in a formula as a shorthand p + scale_y_continuous(sec.axis = ~.^2)