Question

I’m trying to remove the space between the y-axis line and the first tick mark in my plot. Here’s an example:

set.seed(201)
n <- 100
dat <- data.frame(xval = (1:n+rnorm(n,sd=5))/20, yval = 2*2^((1:n+rnorm(n,sd=5))/20))
dat[dat[,1] < 0,1] <- 0
dat[dat[,2] < 0,2] <- 0

ggplot(dat, aes(xval, yval)) + geom_point()

This code plots a graphic with a space between the y-axis line and the zero tick mark in the x-axis. How can I remove it?

Answer 1

You can alter this “gap” using the scale_x_continuous function:

ggplot(dat, aes(xval, yval)) + geom_point() + 
  scale_x_continuous(expand=c(0,0))

From the help file on scale_x_continuous,

expand: numeric vector of length two giving multiplicative and
additive expansion constants. These constants ensure that the data is
placed some distance away from the axes.

To alter the space on the y-axis, use scale_y_continuous