coatless-rpkg / cetcolor

CET Perceptually Uniform Colour Maps for R

cetcolor

The cetcolor package is designed to bring to R the 56 colour maps created by Peter Kovesi that avoid points of locally high colour contrast leading to the perception of false anomalies in your data when there is none. The colour maps have been designed to avoid this phenomenon by having uniform perceptual contrast over their whole range.

Installation

The cetcolor package is available on both CRAN and GitHub. The CRAN version is considered stable while the GitHub version is in a state of development and may break.

You can install the stable version of the cetcolor package with:

install.packages("cetcolor")

For the development version, you can opt for:

install.packages("remotes")
remotes::install_github("coatless-rpkg/cetcolor")

Sample Usage

# Load the Library
library("cetcolor")

# Get RGB Hexadecimals for graphing
cet_pal(5, name = "blues")
#> [1] "#F1F1F1" "#C0D3EB" "#93B5DD" "#7197C1" "#3B7CB2"

# Sample use with ggplot2
library("ggplot2")

ggplot(faithfuld, aes(waiting, eruptions)) +
  geom_raster(aes(fill = density)) +
  theme_bw() + theme(panel.grid=element_blank()) -> g

library("gridExtra")

# Frequently used colour maps have "nicknames" see ?cet_color_maps 
grid.arrange(
  g + scale_fill_gradientn(colours = cet_pal(5, name = "fire")),
  g + scale_fill_gradientn(colours = cet_pal(5, name = "inferno")),
  g + scale_fill_gradientn(colours = cet_pal(5, name = "blues")),
  g + scale_fill_gradientn(colours = cet_pal(5, name = "kgy")),
  ncol = 2, nrow = 2
)

# Show a panel of possible values (without nicknames)
display_cet_all()

References

CET

• CET Perceptually Uniform Colour Maps: Download Page
  • Location of CSV data, references, and data.
• colorcet for Python
  • Shorthand naming of colour schemes and presentation of palettes
• PerceptualColourMaps.jl by Peter Kovesi
  • Referenced documentation and possible reimplementation of generation functions to avoid using CSV data.

R Colour Palettes

• viridis (Source)
  • Provides MATLAB perceptually uniform colour maps in a manner that is similar to this package.
• RColorBrewer (Source)
  • Function interface naming, e.g. cet_pal(n, name), and colour map displays.
• scales and ggplot2
  • Proper ways to interface colour palettes with ggplot2 as shown for RColorBrewer.

Future

• Allow for n > 256.
• Provide hooks for ggplot2 gradient and discrete scales
• Port over the Peter’s generation code from Julia / MATLAB to R.

Authors

James Balamuta and Peter Kovesi

License

CC BY-SA 4.0

cetcolor's Issues

Glasbey palettes

For those who came here looking for a Python colorcet implementation, you'll find the Glasbey palettes missing.

These can be converted quite easily though. Download the assets folder from colorcet then:

  GlasbeyCsvDir <- r"(...\)"  
  fn <- glue("{GlasbeyCsvDir}glasbey_hv_n256.csv")
  
  data <- readr::read_csv( fn,
                   col_names = c("R", "G", "B"),
                   col_types = c("d", "d", "d")
                   )  
  glPal <- rgb(data)

Not as convenient as the cetcolor package of course.

Rename color palettes to new code system

Switch naming scheme to codes

Dropped the CET- prefix and use lowercase letters, e.g. d1, i1, ...

c.f.

In practice I simply refer to the colour maps by a number prefixed by one or two characters to indicate whether the map is linear (l), diverging (d), rainbow (r), cyclic(c), isoluminant (i) or colour blind (cb). Thus, for example, the linear greyscale is 'l1' or 'cet-l1', the heat colour map is 'l3' or 'cet-l3' and the blue-white-red diverging map is 'd1' or 'cet-d1' etc, etc. In the visual catalogue shown further below you will see each colour map with both its simple and complex names.

https://peterkovesi.com/projects/colourmaps/

Update color maps to include additions in May 2018

c.f. https://peterkovesi.com/projects/colourmaps/

Note: Update May 2018: New colour maps L16-L19, D1A and D13

WIP in #6

Update to latest version of palette namings

@peterkovesi do you by chance have any update notes as to how the color palettes have changed recently? Anything with respect to the rename of old palettes found in 2018.

I'm seeing a bunch of new names and existing palettes having ~3 decimal places instead of 5 decimal places.

82ec912

Allow for n > 256.

Figure out a way to get a more generalized gradient so plots using greater than 256 colors can be used.

Release 0.1.0 - `cetcolor`

• Run against winbuilder
• Update NEWS.md
• Update DESCRIPTION version number
• Mark a new release upon CRAN upload

Provide hooks for ggplot2 gradient and discrete scales

Think about adding some hooks for ggplot2... (Package will have more dependencies though... )

Add unit tests

No code coverage at the moment.

Could be useful in the future.