[R] Adding a legend to a (multi-facet) plot produced by ggplot().

[Rolf Turner]

On 2/12/19 5:08 pm, Rui Barradas wrote:
> Hello,
> 
> Here are two ways of drawing the lines black and at the same time 
> removing the lines in the legend. The second way is more idiomatic.
> 
> 
> 1. Override the colour setting in the ggplot call when drawing the lines:
> 
> geom_line(aes(y = y1), colour = "black") +
> 
> 
> 2. Don't set the colour aesthetic in the initial ggplot call. It will be 
> needed only to draw the points, so set it in geom_point(). Though it 
> doesn't influence the lines' colour and the lines in the legend, the 
> same principle applies to shape = variable so I have moved it to 
> geom_point().
> 
> The complete instruction becomes:
> 
> 
> ggplot(long, aes(x, y = value)) +
>    geom_line(aes(y = y1)) +
>    geom_point(aes(colour = variable, shape = variable)) +
>    scale_colour_manual("Doesn't work",values=c("blue","red"),
>                        labels=c("clyde","irving")) +
>    scale_shape_manual("Doesn't work",values=c(16,3),
>                       labels=c("clyde","irving")) +
> 
>    facet_grid(cols=vars(grp))
> 
> 
> 
> Hope this helps.

Boy did it *ever*!!!  Perfect. Thank you *HUGELY*!!!

cheers,

Rolf

-- 
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276