[HN Gopher] Scientific colour maps
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Scientific colour maps
Author : legrande
Score : 54 points
Date : 2023-06-15 16:18 UTC (6 hours ago)
(HTM) web link (www.fabiocrameri.ch)
(TXT) w3m dump (www.fabiocrameri.ch)
| angry_moose wrote:
| I've tried using these before and it always progresses as
| follows:
|
| > Why are you using such ugly colors? This is weird, just use a
| rainbow plot, everyone knows what a rainbow plot is. We're not
| approving these reports until you change it to a rainbow plot.
|
| About 90% of the time rainbow plots just encode "blue=no problem;
| red=problem; everything else=kinda interesting" so it works out
| fine anyway.
|
| Sometimes I can sneak a red/blue gradient through, but its rare.
| crazygringo wrote:
| Can you give more context? What industry/department are you in
| and what kinds of reports?
|
| My general experience has been the opposite -- is that anytime
| you can produce something that feels more elegant or
| "design"-y, with well-chosen tasteful colors instead of ugly
| primary colors, that it's extremely well received, and the
| problem is that coworkers ask me to improve their own
| charts/presentations which I'm not going to do (but I will send
| them links to a site like this). But this is in the context of
| presentations at tech companies.
| angry_moose wrote:
| Physics simulations - Structural/FEA and Fluid Flow/CFD. I've
| bounced through aerospace, transportation, and medical over
| the years and its pretty much been the same everywhere.
|
| Management/stakeholders are used to rainbow plots, and
| haven't had much appetite for anything else (unless the
| software doesn't give the option).
| apwheele wrote:
| I tend to think the continuous color palettes don't look very
| nice (no matter what the colors are) in various data
| visualizations. So I often prefer the color brewer discrete
| smaller sets,
| https://colorbrewer2.org/#type=sequential&scheme=BuGn&n=3
|
| I use the viridis inferno on occasion as well,
| https://github.com/sjmgarnier/viridis, although sometimes it is
| too dark.
| jbay808 wrote:
| On this note, is anyone aware of any _two-dimensional_ colourmaps
| that are perceptually-uniform (or close to it), or perhaps
| periodic?
|
| I find I often have to hand-roll these myself.
| kanbara wrote:
| what a coincidence, just been going thrubour grafana dashboards
| and setting heatmaps to at least perceptually uniform colour
| maps. this is great
| afterburner wrote:
| > perceptually uniform colour maps
|
| Thank you, googling this led me to the following, which
| thankfully has quick-loading images as examples (as opposed to
| the janky OP link)
|
| https://colorcet.com/
| [deleted]
| mrwnmonm wrote:
| No
| bee_rider wrote:
| The one they call Batlow seems quite similar to the color scheme
| Matplotlib calls Cubehelix. I quite like it, particularly
| reversed (cubehelix_r); it goes to white near zero, which is nice
| when plotting sparse data, is sequential (which is of course
| table-stakes for accessibility/black and white printing reasons),
| but the different colors make it easy eyeball "tiny/medium/huge"
| points.
| JBorrow wrote:
| Cubehelix is not a matplotlib colour map, though it is
| available in their defaults :)
|
| https://www.mrao.cam.ac.uk/~dag/CUBEHELIX/
| kardos wrote:
| Also see https://matplotlib.org/cmocean/
| SubiculumCode wrote:
| on my way out the door... Can these be used in R?
| LordDragonfang wrote:
| The web design is awful, since they shove this information
| nearly a full screen below the fold on desktop (below a bunch
| of corporate logos??), and several screens down on mobile, but
| yes:
|
| >Built for (almost) everything
|
| >MatLab, Python, Julia, R, GMT, QGIS, Ncview, Ferret, Plotly,
| Paraview, VisIt, Mathematica, Gnuplot, Surfer, d3, SKUA-GOCAD,
| Petrel, XMapTools, COMSOL Multiphysics, Fledermaus, Qimera,
| ImageJ, Fiji, Kingdom, Originlab, GIMP, Inkscape, Adobe
| Photoshop, and more...
| drvd wrote:
| Unfortunately the gnuplot palettes are broken (but easy to
| fix).
| mapierce2 wrote:
| Relevant:
|
| https://personal.sron.nl/~pault/
| LordDragonfang wrote:
| Relevant:
|
| http://jakevdp.github.io/blog/2014/10/16/how-bad-is-your-col...
|
| https://matplotlib.org/2.0.2/users/colormaps.html
| shrx wrote:
| They claim that "[t]he colour gradients are perceptually uniform
| and ordered to represent data both fairly, without visual
| distortion, and intuitively", however on my calibrated screen
| many gradients are visibly biased with non-uniform gradients,
| especially near the darker end. Most noticeable examples include
| "batlowK", "lipari", "navia" and even "grayC" which is a
| grayscale gradient.
|
| edit: missed a part of the quote
| splittingTimes wrote:
| Mentioned in the text is IBM, which did research back in the 90s
| on perceptually-based colormaps and how to best represent various
| types of data within the color dimensions of luminescence,
| saturation and hue [1]. For example, they found that,
|
| (1) Hue was not a good dimension for encoding magnitude
| information, i.e. rainbow color maps are bad.
|
| (2) The mechanisms in human vision responsible for high spatial
| frequency information processing are luminance channels. If the
| data to be represented have high spatial frequency, use a color
| map which has a strong luminance variation across the data range.
|
| (3) For interval and ratio data, both luminance- and saturation-
| varying color maps should produce the effect of having equal
| steps in data value correspond to equal perceptual steps, but the
| first will be most effective for high spatial frequency data
| variations and the second will be most effective for low spatial
| frequency variations.
|
| ===
|
| [1] the original link got removed from IBMs website. Back in the
| day it was under
|
| https://www.research.ibm.com/people/l/lloydt/color/color.HTM
|
| A pdf copy is here:
|
| https://github.com/frankMilde/interesting-reads/blob/master/...
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