How do I color ggplot lines and adjust the legend?

Question

I am trying to color my lines in ggplot to be red and blue, but they seem to have reversed colors.

ggplot(data.frame(x)) +
  geom_line(aes(x=x, y=y, color='blue')) +
  geom_line(aes(x=x, y=y2, color='red')) +
  labs(title ="Normal Distribution Curve & Normal CDF Curve ")

To that end, how can I override the text in the legend to not say "red" and "blue" but instead be labeled "distribution 1" and "distribution 2"?

It's not that they've reversed colors, it's that you need to assign a variable to color, the way ggplot expects. Then if you have specific colors you want to use, you set a scale. Take a look through the [docs](http://ggplot2.tidyverse.org/), which have a lot of examples and link to tutorials — camille, Jan 31 '20 at 23:03
So: `ggplot(data.frame(x)) + geom_line(aes(x=x, y=y, color='distribution 1')) + geom_line(aes(x=x, y=y2, color='distribution 2')) + scale_color_manual(values = c("navy", "firebrick"))`. — Axeman, Jan 31 '20 at 23:41

score 0 · Accepted Answer · answered Jan 31 '20 at 23:19

You can repeat your x values twice, and put them under the same data frame with y1 and y2, this is the long format:

x = seq(-5,5,by=0.1)
y = dnorm(x,0,1)
y2 = dnorm(x,1,0.25)
dat = data.frame(
x = rep(x,2),
y = c(y,y2),
type = rep(c("distribution 1","distribution 2"),each=length(x))
)

ggplot(dat,aes(x=x,y=y,color=type)) +
  geom_line() +
  scale_color_manual(values=c("blue","red"))+
  labs(title ="Normal Distribution Curve & Normal CDF Curve ")

How do I color ggplot lines and adjust the legend?

1 Answers1