Violin plots in ggplot2

Use geom_violin() to quickly plot a visual summary of variables, using the Boston dataset, MASS library.

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Use geom_violin() to quickly plot a visual summary of variables, using the Boston dataset from the MASS library.

1. Upload the relevant libraries:

require(tidyr)
require(ggplot2)
require(RColorBrewer)
require(randomcoloR)
require(MASS)

2. Load data and use the tidyr package to transform wide into long format:

data(Boston)
dt.long <- gather(Boston, "variable",
"value", crim:medv)

3. Create some color palettes:

col <- colorRampPalette(c("red", "blue"))(14)
# col.bp <- brewer.pal(9, "Set1") # brewer.pal only has a max of 9 colors
col.rc <- as.vector(distinctColorPalette(14))

4. Plot(s):

  • With the standard colors produced by ggplot2:
ggplot(dt.long,aes(factor(variable), value))+
geom_violin(aes(fill=factor(variable)))+
geom_boxplot(alpha=0.3, color="black", width=.1)+
labs(x = "", y = "")+
theme_bw()+
theme(legend.title = element_blank())+
facet_wrap(~variable, scales="free")

violin-ggplot-color

  • With the color palette produced by colorRampPalette:
ggplot(dt.long,aes(factor(variable), value))+
geom_violin(aes(fill=factor(variable)))+
geom_boxplot(alpha=0.3, color="black", width=.1)+
labs(x = "", y = "")+
scale_fill_manual(values = col, name="")+
theme_bw()+
facet_wrap(~variable, scales="free")

violin-auto-color

  • With the color palette produced by randomcoloR library:
ggplot(dt.long,aes(factor(variable), value))+
geom_violin(aes(fill=factor(variable)))+
geom_boxplot(alpha=0.3, color="black", width=.1)+
labs(x = "", y = "")+
scale_fill_manual(values = col.rc, name="")+
theme_bw()+
facet_wrap(~variable, scales="free")

violin-rc-color

Author: acarioli

is a PostDoc at the Geography and Environment department of the University of Southampton, WorldPop project team. She is also affiliated researcher at CED, UAB and Dondena Centre. Her interests include spatial econometrics and modeling, bayesian methods, machine learning processes, forecasting, micro-data simulation, and data visualization. Demo-traveler, Mac enthusiast, R zealot and Rladies member.