Perceptually uniform continuous colormaps from CET#

Peter Kovesi at the Center for Exploration Targeting created a very useful set of perceptually uniform continuous colormaps, many of which can replace the highly non-uniform colormaps provided with Python plotting programs. Here we will show how to use them via a Python package named colorcet, listing all the ones available and allowing you to evaluate how perceptually uniform they are for you, your particular monitor, etc. Download and installation instructions are at the github site.

We will plot them using Matplotlib via Holoviews, but identical Bokeh palettes are also provided, and both Bokeh palettes and Matplotlib colormaps are usable in Datashader. Thus these colormaps can be used in any of those Python packages, as well as any other package that accepts a Python list of normalized RGB tuples or hex colors. See Peter’s site to download versions for other non-Python packages.

import holoviews as hv
from colorcet.plotting import swatches, sine_combs