Post #290

#DS#Visualization Okay, I'll tell you the reason I wrote this post. It is because xkcd made [this](https://xkcd.com/2537/). --- Choosing proper colormaps for our visualizations is important. It's almost like shooting a photo using your phone. Some phones capture details in every corner, while some phones give us overexposed photos and we get no details in the bright regions. A proper colormap should make sure we see the details we need to see. To address the importance of colormaps, we use the two examples shown on the website of colorcet[^colorcet]. The two colormaps, hot, and fire, can be found in matplotlib and colorcet, respectively. I can not post multiple images in one message, please see the full post for the comparisons of the two colormaps. Really, it is amazing. Find the link below: https://github.com/kausalflow/community/discussions/20 It is clear that "hot" brings in some overexposure. The other colormap, "fire", is a so-called perceptually uniform colormap. More experiments are performed in colorcet. Glasbey et al showed some examples of inspecting different properties using different colormaps[^Glasbey2007]. One of the methods to make sure the colormap shows enough details is to use perceptually uniform colrmaps[^Kovesi2015]. Kovesi provides a method to validate if a color map has uniform perceptual contrast[^Kovesi2015]. --- References and links mentioned in this post: [^colorcet]: Anaconda. colorcet 1.0.0 documentation. [cited 12 Nov 2021]. Available: https://colorcet.holoviz.org/ [^colorcet-github]: holoviz. colorcet/index.ipynb at master · holoviz/colorcet. In: GitHub [Internet]. [cited 12 Nov 2021]. Available: https://github.com/holoviz/colorcet/blob/master/examples/index.ipynb [^Kovesi2015]: Kovesi P. Good Colour Maps: How to Design Them. arXiv [cs.GR]. 2015. Available: http://arxiv.org/abs/1509.03700 [^Glasbey2007]: Glasbey C, van der Heijden G, Toh VFK, Gray A. Colour displays for categorical images. Color Research & Application. 2007. pp. 304–309. doi:10.1002/col.20327 [^matplotlib-colormaps]: Choosing Colormaps in Matplotlib — Matplotlib 3.4.3 documentation. [cited 12 Nov 2021]. Available: https://matplotlib.org/stable/tutorials/colors/colormaps.html