CET Perceptually Uniform Colour Maps

James Balamuta with material heavily taken from Peter Kovesi

2017-08-05

The cetcolor package is designed to bring to R the color maps created by Peter Kovesi in Kovesi (2015) 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.

This vignette attempts to summarize information presented at http://peterkovesi.com/projects/colourmaps/.

Supported Colour Maps

There are 51 supported colour maps organised according to the attributes:

Organisation of Colour Maps

Each colour map is named as follows:

                    linear_kryw_5-100_c67_n256
                      /      /    |    \    \
Colour map attribute(s)     /     |     \    Number of colour map entries
                           /      |      \
     String indicating nominal    |       Mean chroma of colour map
     hue sequence.                |
                              Range of lightness values

Moreover, the colour map name may contain cyclic shift information as well as indicating whether it has been reversed by a flag.

              cyclic_wrwbw_90-40_c42_n256_s25_r
                                          /    \
                                         /   Indicates that the map is reversed.
                                        / 
                   Percentage of colour map length
                   that the map has been rotated by.

Colour Maps

Linear

library("cetcolor")
display_cet_attribute(attribute = "linear")

Diverging

display_cet_attribute(attribute = "diverging")

Rainbow

display_cet_attribute(attribute = "rainbow")

Cyclic

display_cet_attribute(attribute = "cyclic")

Isoluminant

display_cet_attribute(attribute = "isoluminant")

Overall

display_cet_all()

Kovesi, Peter. 2015. “Good Colour Maps: How to Design Them.” CoRR abs/1509.03700. http://arxiv.org/abs/1509.03700.