1 Introduction

My eyes were finally opened and I understood nature.

I learned at the same time to love it.

— Claude Monet

The ggsci package offers a collection of high-quality color palettes inspired by colors used in scientific journals and science fiction TV shows.

2 Available Palettes

The color palettes in ggsci are available as ggplot2 scales. For discrete palettes, the scales are named as:

• scale_color_palname()
• scale_fill_palname()

We also provided aliases, such as scale_colour_palname() for scale_color_palname(). All available palettes are listed in the table below:

Next, we use scatterplots with smooth curves, and bar plots to demonstrate the discrete color palettes:

library("ggsci")
library("ggplot2")
library("gridExtra")

data("diamonds")

p1 = ggplot(subset(diamonds, carat >= 2.2),
       aes(x = table, y = price, colour = cut)) +
  geom_point(alpha = 0.7) +
  geom_smooth(alpha = 0.05, size = 1, span = 1) +
  theme_bw()

p2 = ggplot(subset(diamonds, carat > 2.2 & depth > 55 & depth < 70), 
       aes(x = depth, fill = cut)) +
  geom_histogram(colour = "black", binwidth = 1, position = "dodge") +
  theme_bw()

p1_npg = p1 + scale_color_npg()
p2_npg = p2 + scale_fill_npg()
grid.arrange(p1_npg, p2_npg, ncol = 2)

p1_aaas = p1 + scale_color_aaas()
p2_aaas = p2 + scale_fill_aaas()
grid.arrange(p1_aaas, p2_aaas, ncol = 2)

p1_lancet = p1 + scale_color_lancet()
p2_lancet = p2 + scale_fill_lancet()
grid.arrange(p1_lancet, p2_lancet, ncol = 2)

p1_jco = p1 + scale_color_jco()
p2_jco = p2 + scale_fill_jco()
grid.arrange(p1_jco, p2_jco, ncol = 2)

p1_ucscgb = p1 + scale_color_ucscgb()
p2_ucscgb = p2 + scale_fill_ucscgb()
grid.arrange(p1_ucscgb, p2_ucscgb, ncol = 2)

p1_uchicago = p1 + scale_color_uchicago()
p2_uchicago = p2 + scale_fill_uchicago()
p1_uchicago_light = p1 + scale_color_uchicago("light")
p2_uchicago_light = p2 + scale_fill_uchicago("light")
p1_uchicago_dark  = p1 + scale_color_uchicago("dark")
p2_uchicago_dark  = p2 + scale_fill_uchicago("dark")
grid.arrange(p1_uchicago,       p2_uchicago,
             p1_uchicago_light, p2_uchicago_light,
             p1_uchicago_dark,  p2_uchicago_dark,
             ncol = 2, nrow = 3)

p1_simpsons = p1 + scale_color_simpsons()
p2_simpsons = p2 + scale_fill_simpsons()
grid.arrange(p1_simpsons, p2_simpsons, ncol = 2)

p1_rickandmorty = p1 + scale_color_rickandmorty()
p2_rickandmorty = p2 + scale_fill_rickandmorty()
grid.arrange(p1_rickandmorty, p2_rickandmorty, ncol = 2)

3 Non-ggplot2 Graphics

To apply the color palettes in ggsci to other graphics systems (such as base graphics and lattice graphics), simply use the palette generator functions in the table above. For example:

mypal = pal_npg("nrc", alpha = 0.7)(9)
mypal

## [1] "#E64B35B2" "#4DBBD5B2" "#00A087B2" "#3C5488B2" "#F39B7FB2" "#8491B4B2"
## [7] "#91D1C2B2" "#DC0000B2" "#7E6148B2"

library("scales")
show_col(mypal)

You will be able to use the generated hex color codes for such graphics systems accordingly. The transparent level of the entire palette is easily adjustable via the argument "alpha" in every generator or scale function.

4 Discussion

Please note some of the palettes might not be the best choice for certain purposes, such as color-blind safe, photocopy safe, or print friendly. If you do have such considerations, you might want to check out color palettes like ColorBrewer and viridis.

The color palettes in this package are solely created for research purposes. The authors are not responsible for the usage of such palettes.

Project website: ggsci.net