set only lower bound of a limit for ggplot

Question

Is it possible to only set the lower bound of a limit for continuous scale? I want to make all my plots 0 based without needing to specify the upper limit bound.

e.g.

+ scale_y_continuous(minlim=0)

Answer 1

You can use expand_limits

ggplot(mtcars, aes(wt, mpg)) + geom_point() + expand_limits(y=0)

Here is a comparison of the two:

• without expand_limits

• with expand_limits

As of version 1.0.0 of ggplot2, you can specify only one limit and have the other be as it would be normally determined by setting that second limit to NA. This approach will allow for both expansion and truncation of the axis range.

ggplot(mtcars, aes(wt, mpg)) + geom_point() +
  scale_y_continuous(limits = c(0, NA))

specifying it via ylim(c(0, NA)) gives an identical figure.

Answer 2

How about using aes(ymin=0), as in:

ggplot(mtcars, aes(wt, mpg)) + geom_point() + aes(ymin=0)

Answer 3

You can also try the following code which will give you the min y-axis at zero and also without the extra gap between x-axis and min y value.

scale_y_continuous(limits = c(0, NA), expand = c(0,0))

Answer 4

I don't think you can do this directly. But as a work-around, you can mimic the way that ggplot2 determines the upper limit:

scale_y_continuous(limits=c(0, max(mydata$y) * 1.1))