Question

I am trying to create a barplot using ggplot2, with the y axis starting at a value greater than zero.

Lets say I have the means and standard errors for hypothetical dataset about carrot length at three different farms:

carrots<-NULL
carrots$Mean<-c(270,250,240)
carrots$SE<-c(3,4,5)
carrots$Farm<-c("Plains","Hill","Valley")
carrots<-data.frame(carrots)

I create a basic plot:

p<-ggplot(carrots,aes(y=Mean,x=Farm)) +
   geom_bar(fill="slateblue") +
   geom_errorbar(aes(ymin=Mean-SE,ymax=Mean+SE), width=0)
p

This is nice, but as the scale runs from 0 to it is difficult to see the differences in length. Therefore, I would like to rescale the y axis to something like c(200,300). However, when I try to do this with:

p+scale_y_continuous('Length (mm)', limit=c(200,300))

The bars disappear, although the error bars remain.

My question is: is it possible to plot a barplot with this adjusted axis using ggplot2?

Thank you for any help or suggestions you can offer.

Answer 1

Try this

p + coord_cartesian(ylim=c(200,300))

Setting the limits on the coordinate system performs a visual zoom;
the data is unchanged, and we just view a small portion of the original plot.