ggplot2 custom scale color labels

Question

I have

norm.values<-data.frame(x=rnorm(100), y=rnorm(100), col=rnorm(100), size=sample(c(1,2,3), 100, replace = T))

ggplot(norm.values , aes(x=x, color=col, y=y)) + 
  geom_point(aes(shape=factor(size)), size=3 ) + 
  scale_color_gradient2(low="blue",mid="blue", high="red") + 
  xlab("chi lab") + 
  ylab("psi lab") +
  labs(color = "Kolor Lab" )+
  labs(shape = "Size Lab", size=20) +
  theme_classic() +
  theme(axis.text=element_text(size=14), axis.title=element_text(size=16), legend.text=element_text(size=18), strip.text.x = element_text(size = 14), strip.text.y = element_text(size = 14),  legend.title =   element_text(size = 18))

In the color legend Kolor Lab I would like the label for red to be >2instead of 2 . Is this possible?

Answer 1

Just add the breaks and labels argument of scale_color_gradient2:

ggplot(norm.values , aes(x=x, color=col, y=y)) + 
  geom_point(aes(shape=factor(size)), size=3 ) + 
  scale_color_gradient2(low="blue",mid="blue", high="red",
                       breaks=c(2,1,0,-1,-2),
                       labels = c(">2", "1", "0", "-1", "-2"))+
  xlab("chi lab") + 
  ylab("psi lab") +
  labs(color = "Kolor Lab" )+
  labs(shape = "Size Lab", size=20) +
  theme_classic() +
  theme(axis.text=element_text(size=14), axis.title=element_text(size=16), legend.text=element_text(size=18), strip.text.x = element_text(size = 14), strip.text.y = element_text(size = 14),  legend.title =   element_text(size = 18))