I’m trying to add horizontal lines to a line graph (sig curve) and I’d like the horizontal lines to meet the line graph and not go past. I have an example of what I’m hoping to do below:
Included is an example of data. Right now, using ggplot, I can create the horizontal lines using geom_hline but I want the horizontal lines to stop once they hit the plotted lines.
df<-data.frame(Points=c(-5.5,-1,-.5,0,.5,1,1.5,2,5.5),X=c(.002,.1,.15,.17,.18,.2,.25,.3,.7))
df2<-data.frame(Points=seq(-10,10,by=.1),X=c(0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.02, 0.04, 0.04, 0.04, 0.04, 0.04, 0.04, 0.04, 0.04, 0.04, 0.04, 0.04, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.05, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.07, 0.07, 0.07, 0.07, 0.07, 0.08, 0.08, 0.08, 0.08, 0.09, 0.09, 0.09, 0.09, 0.1, 0.1, 0.1, 0.1, 0.11, 0.11, 0.11, 0.12, 0.12, 0.12, 0.13, 0.13, 0.15, 0.15, 0.15, 0.16, 0.16, 0.17, 0.17, 0.18, 0.18, 0.19, 0.19, 0.2, 0.2, 0.21, 0.22, 0.22, 0.22, 0.23, 0.23, 0.24, 0.25, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.3, 0.31, 0.31, 0.32, 0.33, 0.34, 0.36, 0.36, 0.37, 0.38, 0.39, 0.39, 0.41, 0.42, 0.42, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.61, 0.62, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7, 0.71, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.88, 0.89, 0.9, 0.9, 0.91, 0.92, 0.92, 0.93, 0.93, 0.94, 0.94, 0.95, 0.95, 0.96, 0.96, 0.96, 0.97, 0.97, 0.97))
ggplot(df2,aes(x=Points,y=X))+geom_line()+geom_hline(yintercept=df$X, col="red")
>Solution :
df$Points2 = approx(df2$X, df2$Points, df$X)$y
ggplot(df2,aes(x=Points,y=X))+geom_line()+
geom_segment(aes(x = -Inf, xend = Points2,
y = X, yend = X),
data = df)
