How to avoid the box in legend key when using aes(fill=kind) in both geom_bar and geom_smooth?

user_7334572 0
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When using aes(fill=kind) in both geom_bar and geom_smooth, I could not get a clean legend and the same plot as follows : Result I wish

This is the script:

#!/usr/bin/env Rscript

## load
library(ggplot2)
library(dplyr)

mma <- data.frame(kind=c(rep('A',100), rep('BB', 100), rep('CC',100)),
                  group=c(rep(seq(0.1, 10, by=0.1),3)),
                  frac=runif(n=300, min=0, max=1))

### pic
wd <- 0.05
posa <- position_dodge(width=wd)
ppa <- ggplot(data=mma, aes(x=group, y=frac, group=kind))+
    geom_bar(aes(fill=kind), stat='identity', position=posa, width=wd)+
    geom_smooth(aes(fill=kind, color=kind), method="loess", span=0.15, size=0.5)+
    labs(x="Time", y="Populations")+
    ## default   mina.png
    ## guides(fill=guide_legend(ncol=3, byrow=TRUE), color="none")+    # minb.png
    ## guides(color=guide_legend(ncol=3, byrow=TRUE), fill="none")+    # minc.png
    theme(legend.position=c(0.66, 0.92),
          legend.key.size=unit(0.56, 'lines'))

### output
pf <- c(3, 7)
ggsave(file = "./mina.png", height = pf[1], width = pf[2])

  • output of default setting (mina.png) mina.png

  • disable color (minb.png) minb.png

  • disable fill (minc.png) minc.png

I dont know why there is a blue line and a frame in the legend of minb.png (It seems if comes from geom_smooth).

I know the gray rect/box in minc.png could omit by using alpha=1 in geom_smooth. However, it will also erase the span region of loess line.

ggplot2 r
2 Answers

You could add show.legend = FALSE in your geom_smooth:

library(tidyverse)

mma <- data.frame(kind=c(rep('A',100), rep('BB', 100), rep('CC',100)),
                  group=c(rep(seq(0.1, 10, by=0.1),3)),
                  frac=runif(n=300, min=0, max=1))

### pic
wd <- 0.05
posa <- position_dodge(width=wd)
ggplot(data=mma, aes(x=group, y=frac, group=kind))+
  geom_bar(aes(fill=kind), stat='identity', position=posa, width=wd)+
  geom_smooth(aes(fill=kind, color=kind), method="loess", span=0.15, size=0.5, show.legend = FALSE)+
  labs(x="Time", y="Populations")+
  ## default   mina.png
  guides(fill=guide_legend(ncol=3, byrow=TRUE), color="none")+    # minb.png
  ## guides(color=guide_legend(ncol=3, byrow=TRUE), fill="none")+    # minc.png
  theme(legend.position=c(0.66, 0.92),
        legend.key.size=unit(0.56, 'lines'))
#> `geom_smooth()` using formula 'y ~ x'

Created on 2022-04-28 by the reprex package (v2.0.1)

user_73270580

If I understand you correctly, you want a clean fill legend and color legend side-by-side as in your picture at the top of the question. In this case, you can achieve the effect using guides:

ggplot(mma, aes(group, frac, fill = kind, color = kind)) +
  geom_col(position = posa, width = wd) +
  geom_smooth(method = "loess", span = 0.15, size = 0.5) +
  labs(x = "Time", y = "Populations", color = 'kind ') +
  guides(fill   = guide_legend(override.aes = list(colour = NA, alpha = 1)),
         colour = guide_legend(override.aes = list(fill = 'white', alpha = 1))) +
  theme(legend.position  = c(0.66, 0.92),
        legend.key.size  = unit(0.56, 'lines'),
        legend.direction = 'horizontal',
        legend.box       = 'horizontal')

enter image description here

user_125003150
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