Ggplot with more than two legends

Question

I have a data.frame which I'd like to scatter plot using ggplot. The data have 3 factors whose levels I'd like to show in the legend, although the color of the points will only be according to one of these factors (df$group below).

Here's what I have so far:

set.seed(1)
df <- data.frame(x=rnorm(100),y=rnorm(100),
                 group=LETTERS[sample(5,100,replace=T)],
                 type=letters[sample(3,100,replace=T)],
                 background=sample(4,100,replace=T),stringsAsFactors=F)

df$group <- factor(df$group,LETTERS[1:5])
df$type <- factor(df$type,;etters[1:3])
df$background <- factor(df$background,c(1:4))

I manually specify colors:

require(RColorBrewer)
require(scales)
all.colors <- hcl(h=seq(0,(12-1)/(12),length=12)*360,c=100,l=65,fixup=TRUE)
group.colors <- all.colors[1:5]
type.colors <- all.colors[6:8]
background.colors <- all.colors[9:12]

This is what I have for showing the 3 factors in the legend (df$group and df$type):

require(ggplot2)

ggplot(df,aes(x=x,y=y,colour=group,fill=type,alpha=background))+geom_point(cex=2,shape=1,stroke=1)+
  theme_bw()+theme(strip.background=element_blank())+scale_color_manual(drop=FALSE,values=group.colors,name="group")+
  guides(fill=guide_legend(override.aes=list(colour=type.colors,pch=0)))

So my question is how to get background.colors appear in the legend under "background" rather than the gray scale colors chosen by default that currently appear there.

this may be helpful http://stackoverflow.com/questions/41390181/ggplot2-add-separate-legend-each-for-two-y-axes-in-facet-plot — Sathish, Mar 25 '17 at 08:54
Do I understand it correctly that you want to have a grouped color legend? Because if you simply want a third legend you could use width or alpha. — takje, Mar 25 '17 at 09:08
Not sure what a grouped legend is. What I want is simply to have the levels of df$background with background.colors and the title "background" appear in the legend below that of group. — dan, Mar 25 '17 at 15:36

score 0 · Answer 1 · edited May 13 '17 at 06:04

ggplot(df,aes(x=x, y=y, colour=group, fill=type, alpha=background))+ 
  geom_point(cex=2, shape=1, stroke=1) + 
  theme_bw() + 
  theme(strip.background=element_blank()) +
  scale_color_manual(drop=FALSE, values=group.colors, name="group") + 
  guides(fill=guide_legend(override.aes=list(colour=type.colors,pch=0)),
         alpha=guide_legend(override.aes=list(colour=background.colors,pch=0)))

Ggplot with more than two legends

1 Answers1