How to plot a single value on an axis in ggplot2? - r

Question

I want to create a plot, similar to the one below:
set.seed(8)
xpos<-rep(1:4,2)
sample<-rep(c("One Stage","Two Stage"),each=4)
dat<-data.frame(cbind(xpos,choice,sample))
dat$xpos<-as.integer(dat$xpos)
dat$choice<-(c(.2,.4,.3,.22,.17,.03,.081,.035))
dat$sample<-as.character(dat$sample)
ggplot(data=dat, aes(x=xpos, y=choice, group=sample, shape=factor(sample), colour=factor(sample))) +
geom_line(aes(linetype=factor(sample)))+
geom_point(size=3)+
geom_point(aes(x=1, y=0.5),size=3)+
scale_linetype_manual(values=c("longdash", "dotted"))+
scale_x_continuous("Block", breaks=seq(1,4,1),limits=c(0.8,4.2))+
scale_y_continuous("Choice Rates", breaks=seq(0,1,0.2),limits=c(-0.02,1))+
theme_classic(base_size = b.size)+
labs(title="Model predictions" )+ theme(plot.title = element_text(hjust=0.5))+
theme(legend.title =element_blank(),legend.position=c(.8,.85)) + scale_color_grey(start=0.2, end=0.2)
Here is how the graph looks like:
Now, I want the single point to appear on the Y-Axis.
I know that I should change for this the "scale_x_continuous" limits (from 0.8, to 0), but then I get the following graph, which is not what I want:
What can be done?
Here is the final wanted result:
Thanks to the comments below, I realized how to do it:
ggplot(data=dat, aes(x=xpos, y=choice, group=sample, shape=factor(sample),
colour=factor(sample))) +
geom_line(aes(linetype=factor(sample)))+
geom_point(size=3)+
geom_point(aes(x=0.8, y=0.5),size=3)+
scale_linetype_manual(values=c("longdash", "dotted"))+
scale_x_continuous("Block", breaks=seq(1,4,1),limits=c(0.8,4.2),expand=c(0,0))+
coord_cartesian(clip = 'off') +
scale_y_continuous("Checking Rates", breaks=seq(0,1,0.2),limits=c(-0.02,1))+
theme_classic(base_size = b.size)+
labs(title="Model predictions" )+ theme(plot.title = element_text(hjust=0.5))+
theme(legend.title =element_blank(),legend.position=c(.8,.85)) + scale_color_grey(start=0.2, end=0.2)

Answer 1

You should us expand = c(0,0)) in the scale_x_continuous, and add coord_cartesian(clip = 'off') so the points don't get clipped (where half of the shape falls outside the plotting area).
ggplot(data=dat, aes(x=xpos, y=choice, group=sample, shape=factor(sample), colour=factor(sample))) +
geom_line(aes(linetype=factor(sample)))+
geom_point(size=3)+
geom_point(aes(x=1, y=0.5),size=3)+
scale_linetype_manual(values=c("longdash", "dotted"))+
scale_x_continuous("Block", breaks=seq(1,4,1),
limits=c(1,4.2), expand = c(0,0))+
coord_cartesian(clip = 'off') +
scale_y_continuous("Choice Rates", breaks=seq(0,1,0.2),limits=c(-0.02,1))+
labs(title="Model predictions" )+ theme(plot.title = element_text(hjust=0.5))+
theme(legend.title =element_blank(),legend.position=c(.8,.85)) +
scale_color_grey(start=0.2, end=0.2) +
theme_classic()