Changing ggplot2 legend title without altering graphical parameters

Question

I have found many topics about the legend title with ggplot2 but after a couple of hours I have not been able to handle my situation.

Here is the dataset:

> dat
  FACTOR1 FACTOR2 lsmean lower.CL upper.CL
1       A      aa   26.2     25.6     26.8
2       B      aa   24.8     23.9     25.7
3       A      bb   26.0     25.2     26.7
4       B      bb   24.9     23.9     25.9
5       A      cc   24.4     23.9     24.8
6       B      cc   23.9     22.9     25.0
7       A      dd   24.9     24.3     25.6
8       B      dd   23.2     22.3     24.0

And the graphic of interest:

gp0 <- ggplot(dat, aes(x=FACTOR2, y=lsmean, group=FACTOR1, colour=FACTOR1)) 
( gp1 <- gp0 +  geom_line(aes(linetype=FACTOR1), size=.6) + 
    geom_point(aes(shape=FACTOR1), size=3) + 
    geom_errorbar(aes(ymax=upper.CL, ymin=lower.CL), width=.1) +
    geom_errorbar(aes(ymax=upper.CL, ymin=lower.CL), width=.1) ) 

If I use scale_colour_manual() to change the legend title then I get an unexpected additional legend:

gp1 + scale_colour_manual("NEW TITLE",values=c("red","blue"))

I suppress this additional legend with scale_"aes"_manual("guide=none", values=...) but I don't understand how to control the parameters (the style of points and lines):

gp1 + scale_colour_manual("NEW TITLE",values=c("red","blue")) +
    scale_shape_manual(guide = 'none', values=c(1,2))   + 
    scale_linetype_manual(guide = 'none', values=c(1,3))  

Please how to reproduce the first plot with and only with a new legend title ?

Answer 1

You have to set the same title for all aes() attributes you have used, for example, using function labs().

gp1 + scale_colour_manual(values=c("red","blue"))+
    labs(colour="NEW TITLE",linetype="NEW TITLE",shape="NEW TITLE")