ggplot box plot with data points: how to control legend appearance? - r

Question

I tried various options, but I cannot find a way to achieve custom legend appearance (unless I export the figure to power point and edit it there...). I would like the legend to look like in the image below and wonder if that is at all possible:
I do not wish to make any changes in the figure itself:
Here is my sample data and code:
df = data.frame(sex = c(1,1,1,1,1, 2,2,2,2,2),
age_cat = c(1,1,1, 2,2,2, 1,1,1, 2),
score_type = c(1,2, 1,2, 1,2, 1,2, 1,2),
score = c(25,28,18,20,30, 37,40,35,43,45))
df$sex <- factor((df$sex))
df$age_cat <- factor((df$age_cat))
df$score_type <- factor((df$score_type))
windows(width=7, height=7)
library(ggplot2)
df %>%
ggplot( aes(x=score_type, y=score)) +
geom_boxplot(aes(color=sex),outlier.shape = NA, size=1.5, show.legend=T) +
geom_point(aes(color=sex, shape = age_cat, group = sex),
position=position_jitterdodge(dodge.width=0.9), size=3, show.legend=F) +
scale_color_manual(values=c("#0072B2", "#CC79A7"), name="",
labels=c("Male", "Female")) +
scale_shape_manual(name="", labels=c('Younger', 'Older'),
values=c(16, 17)) +
theme_bw()+
theme(panel.border = element_blank(), axis.ticks = element_blank(),
legend.position=c(0.9, 0.65), legend.text=element_text(size=11),
legend.title=element_text(size=11.5),
panel.grid.major.x = element_blank() ,
plot.title = element_text(size=11, face = "bold"),
axis.title=element_text(size=13),
axis.text.y = element_text(size=11),
axis.text.x = element_text(size=11),
plot.margin = unit(c(0.5,0.2,0,0.2), "cm")) +
labs(title= "", x = "",y = "Score") +
scale_y_continuous(breaks=c(0, 20, 40, 60, 80, 100),
labels=c('0', '20', '40', '60', '80', '100')) +
expand_limits(x=5, y=70) +
scale_x_discrete(labels = c("A", "B")) +
coord_cartesian(clip = "off")

Answer 1

You could achieve your desired result by
dropping show.legend=FALSE from geom_point
Overriding the shapes to be displayed in the legend using guides(shape = guide_legend(override.aes = list(shape = c(1, 2))))
library(ggplot2)
ggplot(df, aes(x = score_type, y = score)) +
geom_boxplot(aes(color = sex), outlier.shape = NA, size = 1.5) +
geom_point(aes(color = sex, shape = age_cat, group = sex),
position = position_jitterdodge(dodge.width = 0.9), size = 3
) +
scale_color_manual(
values = c("#0072B2", "#CC79A7"), name = "",
labels = c("Male", "Female")
) +
scale_shape_manual(
name = "", labels = c("Younger", "Older"),
values = c(16, 17)
) +
theme_bw() +
theme(
panel.border = element_blank(), axis.ticks = element_blank(),
legend.position = c(0.9, 0.65), legend.text = element_text(size = 11),
legend.title = element_text(size = 11.5),
panel.grid.major.x = element_blank(),
plot.title = element_text(size = 11, face = "bold"),
axis.title = element_text(size = 13),
axis.text.y = element_text(size = 11),
axis.text.x = element_text(size = 11),
plot.margin = unit(c(0.5, 0.2, 0, 0.2), "cm")
) +
labs(title = "", x = "", y = "Score") +
scale_y_continuous(
breaks = c(0, 20, 40, 60, 80, 100),
labels = c("0", "20", "40", "60", "80", "100")
) +
expand_limits(x = 5, y = 70) +
scale_x_discrete(labels = c("A", "B")) +
coord_cartesian(clip = "off") +
guides(shape = guide_legend(override.aes = list(shape = c(1, 2))))