scale_fill_discrete does not change label names

Question

I've got a problem when trying to change the name of the labels in the legend of a plot using ggplot.

I come to read some tutorials on the topic in Cookbook for R and questions on the same topic in this forum (How do I manually change the key labels in a legend in ggplot2), and some more. The reason I write this is because I cannot understand what is going on with my ggplot function that makes scale_fill_discrete () don't work while in other examples it does.

My data frame is something like:

           x w t
1  0.8972208 A 0
2  0.8312684 A 1
3  0.7504638 A 2
4  0.6563472 A 3
5  0.5764883 A 4
6  0.5224609 A 5
7  0.8972208 B 0
8  0.8456315 B 1
9  0.7674353 B 2
10 0.6689723 B 3
11 0.6114414 B 4
12 0.5381668 B 5
13 0.8983253 C 0
14 0.7878405 C 1
15 0.6955420 C 2
16 0.6179749 C 3
17 0.5524141 C 4
18 0.4966967 C 5    

As far as I know, sorting factors in the legend is a very difficult task using ggplot, and that's the reason why they are ordered alphabetically in the dataframe (factor w). However the real names should be something different ,like: "O", "R" and "N.

The ggplot function I'm ussing is:

ggplot (data = eso3, aes (x=t, y = x, colour = w, linetype = w, shape= w))
  +geom_line()
  +geom_point()
  +scale_linetype_manual("LEGEND TITLE",values =c("solid","solid","dashed","dashed","dotted","dotted"))
  +scale_colour_manual("LEGEND TITLE",values=c("black","black","darkgray","darkgray","dimgray","dimgray"))
  +scale_shape_manual("LEGEND TITLE",values=c(19,15,19,15,19,15))
  +scale_y_continuous("Y LABEL",limits=c(0.0,1.0))
  +theme(axis.title.y = element_text(angle=0))
  +scale_fill_discrete("LEGEND TITLE",breaks=c("A","B","C"),labels=c("O","R","N"))
  +ggtitle("MAIN TITLE")
  +theme_bw()    

I know function scale_fill_discrete should change ("A","B","C") to ("O","R","N"). Why it does not work?

Answer 1

Since you used the colour, linetype and shape but not fill, you have to integrate the new labeles with the scale_xxx_manual()calls like :

ggplot (data = eso3, aes (x=t, y = x, colour = w, linetype = w, shape= w))+
geom_line()+
geom_point()+
scale_linetype_manual("LEGEND TITLE",values =c("solid","solid","dashed","dashed","dotted","dotted"),breaks=c("A", "B", "C"), labels=c("O","R","N"))+
scale_colour_manual("LEGEND TITLE",values=c("black","black","darkgray","darkgray","dimgray","dimgray"),breaks=c("A", "B", "C"), labels=c("O","R","N"))+
scale_shape_manual("LEGEND TITLE",values=c(19,15,19,15,19,15),breaks=c("A", "B", "C"), labels=c("O","R","N"))+
scale_y_continuous("Y LABEL",limits=c(0.0,1.0))+
theme(axis.title.y = element_text(angle=0))+
ggtitle("MAIN TITLE")+
theme_bw()