Axes - R Graphics - page 226

Figure 8-10. Left: scatter plot with equal scaling of axes; right: with tick marks at specified posi-
tions

Discussion
The marathon data set contains runners' marathon and half-marathon times. In this case it might
be useful to force the x- and y-axes to have the same scaling.

It's also helpful to set the tick spacing to be the same, by setting in

breaks

scale_y_continuous() and scale_x_continuous() (also in Figure 8-10 ):

sp + coord_fixed() +
scale_y_continuous(breaks = seq( 0 , 420 , 30 )) +
scale_x_continuous(breaks = seq( 0 , 420 , 30 ))

If, instead of an equal ratio, you want some other fixed ratio between the axes, set the ratio
parameter. With the marathon data, we might want the axis with half-marathon times stretched