[yt-dev] Default colormap

Matthew Turk matthewturk at gmail.com
Thu Jan 21 10:06:23 PST 2016 

Hi folks,

I've put up a comparison image:

http://i.imgur.com/Afxdb0G.jpg

Left is Kacper, middle is me, right is Nathan.

Honestly I think all could go in, but we should pick a default -- whether
it's one of these or a different one.  Anyone have a strong opinion?

-Matt

On Mon, Jan 18, 2016 at 10:19 AM, B.W. Keller <kellerbw at mcmaster.ca> wrote:

> Wow, all of these look great.  I think I like Matt's best for painting our
> bikeshed, but I would be happy with any of them.
>
> On Mon, Jan 18, 2016 at 11:10 AM, Kacper Kowalik <xarthisius.kk at gmail.com>
> wrote:
>
>> On 01/18/2016 09:45 AM, Matthew Turk wrote:
>> > Hi all,
>> >
>> > I've experimented a bit and come up with this:
>> >
>> > https://images.hub.yt/u/fido/m/9bbe3cf6-png/
>> >
>> > The script:
>> >
>> > http://paste.yt-project.org/show/6151/
>> >
>> > This was designed with the viscm project, which is awfully cool.  What
>> > do folks think?  I think Kacper and Nathan also experimented with
>> > viscm and have some ideas too, so maybe we should put it up for an
>> > eventual vote.
>>
>> This is my experiment:
>>
>> https://images.hub.yt/u/fido/m/f180a901-png/
>>
>> Source:
>>
>> http://paste.yt-project.org/show/6166/
>>
>> Cheers,
>> Kacper
>>
>>
>> >
>> > Also, I would campaign for calling whatever our new colormap turns out
>> > to be one of these three things, in increasing order of my preference:
>> >
>> > agar
>> > kelp
>> > kanten
>> >
>> > -Matt
>> >
>> > On Thu, Jan 14, 2016 at 10:57 AM, Matthew Turk <matthewturk at gmail.com>
>> wrote:
>> >> Hi Stuart and everyone else,
>> >>
>> >> This is great info.  I appreciate everyone's thoughtful replies.
>> >>
>> >> Having both a sequential colormap (which would replace algae) and a
>> >> diverging colormap, would be awesome.  The Paraview devs shipped the
>> >> new matplotlib ones (like Inferno) in 5.0.  I think it would be a fun
>> >> experiment to see if we can come up with something sufficiently
>> >> "branded" or different.  And then if we can't, fall back on something
>> >> like Inferno?
>> >>
>> >> -Matt
>> >>
>> >> On Wed, Jan 6, 2016 at 12:48 PM, Levy, Stuart A <salevy at illinois.edu>
>> wrote:
>> >>> There was a fair bit of discussion about colormaps - terrible, useful,
>> >>> beautiful - at IEEE Vis last October.   The viridis colormap was a
>> featured
>> >>> one.   So was the traditional rainbow, which lots of info-vis and
>> perceptual
>> >>> people piled on to criticize.
>> >>>
>> >>> Among design criteria for a continuous-valued colormap is whether it's
>> >>> "sequential" (like the typical yt colormap, or viridis) or
>> "diverging".
>> >>> You'd want a diverging colormap to show signed deviations from a norm
>> -
>> >>> where the eye should be caught by places where a value is either much
>> less
>> >>> than, or much more than, something in the middle.   Is it worth
>> offering a
>> >>> typical divergent colormap, as well as a new typical sequential one,
>> in yt?
>> >>>
>> >>> Note that among the Stefan van der Walt & Nathaniel Smith writeup (
>> >>> http://bids.github.io/colormap/ ) on their development of better
>> cmaps, they
>> >>> use Nathan Goldbaum's galaxy evolution as a test case for six
>> (sequential)
>> >>> examples! =>
>> http://vorpus.org/~njs/goldbaum-galaxies-all-colormaps.mkv
>> >>>
>> >>> A neat web site with sample colormaps - aimed at mapping discrete
>> values on
>> >>> geographic maps, so not directly applicable but cool - is this, by
>> Cynthia
>> >>> Brewer and Mark Harrower at PSU:
>> >>>     http://colorbrewer2.org/
>> >>> It has a library of predesigned cmaps, and lets you sift them by being
>> >>> colorblind-safe, photocopy safe, etc.
>> >>> ________________________________
>> >>> From: yt-dev [yt-dev-bounces at lists.spacepope.org] on behalf of B.W.
>> Keller
>> >>> [kellerbw at mcmaster.ca]
>> >>> Sent: Wednesday, January 06, 2016 12:13
>> >>> To: yt-dev at lists.spacepope.org
>> >>> Subject: Re: [yt-dev] Default colormap
>> >>>
>> >>> There is a really excellent paper on designing color maps called
>> "Color
>> >>> Sequences for Univariate Maps: Theory, Experiments, and Principles"
>> that you
>> >>> can get here:
>> >>>
>> http://ccom.unh.edu/sites/default/files/publications/Ware_1988_CGA_Color_sequences_univariate_maps.pdf
>> >>>
>> >>> If we design a new colormap, this would be a good reference along
>> with those
>> >>> scipy resources.  I personally would love to have an accessible,
>> yt-custom
>> >>> colormap.
>> >>>
>> >>> On Wed, Jan 6, 2016 at 11:50 AM, Erik Schnetter <schnetter at gmail.com>
>> wrote:
>> >>>>
>> >>>> I think there are several colourmaps that were created when Viridis
>> >>>> was invented. I personally like Inferno.
>> >>>>
>> >>>> -erik
>> >>>>
>> >>>> On Wed, Jan 6, 2016 at 11:34 AM, Nathan Goldbaum <
>> nathan12343 at gmail.com>
>> >>>> wrote:
>> >>>>> I would also be for coming up with our own colormap. That said, I
>> think
>> >>>>> simply modifying algae won't be enough, since it is too perceptually
>> >>>>> nonlinear.
>> >>>>>
>> >>>>> On Wed, Jan 6, 2016 at 10:32 AM, John ZuHone <jzuhone at gmail.com>
>> wrote:
>> >>>>>>
>> >>>>>> I would go for modifying algae.
>> >>>>>>
>> >>>>>>> On Jan 6, 2016, at 11:30 AM, Matthew Turk <matthewturk at gmail.com>
>> >>>>>>> wrote:
>> >>>>>>>
>> >>>>>>> Hi folks,
>> >>>>>>>
>> >>>>>>> For a long time we've used "algae," which was designed by Britton
>> >>>>>>> about eight years ago, as the default colormap.  This has been
>> really
>> >>>>>>> nice for "branding" yt -- if you see an algae plot, it's probably
>> >>>>>>> (not
>> >>>>>>> definitely) made with yt.  But it's also not accessible from a
>> >>>>>>> colorblindness perspective.  Stefan van der Walt has been giving
>> some
>> >>>>>>> really great talks lately about building a better colormap for
>> >>>>>>> matplotlib (e.g., https://www.youtube.com/watch?v=xAoljeRJ3lU )
>> which
>> >>>>>>> culminated in viridis, which is shipping in recent versions of
>> >>>>>>> matplotlib and will become the default.
>> >>>>>>>
>> >>>>>>> In support of this, he built a tool called viscm which can
>> generate
>> >>>>>>> reduced versions of colormaps to show what they would be like with
>> >>>>>>> varying degrees of insensitivity to color.  I've generated outputs
>> >>>>>>> from viscm of three of the custom colormaps we ship with yt:
>> >>>>>>>
>> >>>>>>> Algae: https://images.hub.yt/u/fido/m/d275d5e1-png/
>> >>>>>>> Cubehelix: https://images.hub.yt/u/fido/m/8e698928-png/ (I
>> believe
>> >>>>>>> this is now also shipped with MPL)
>> >>>>>>> Kamae: https://images.hub.yt/u/fido/m/e0e40efa-png/
>> >>>>>>>
>> >>>>>>> I love algae, but it's not the best from an accessibility
>> >>>>>>> perspective.
>> >>>>>>>
>> >>>>>>> I'd like to propose that we use a new default colormap.  If we do
>> >>>>>>> this, I see two options:
>> >>>>>>>
>> >>>>>>> * Retain a "branding" by developing a new one either by using the
>> >>>>>>> techniques used by matplotlib (or one of the maps they opted not
>> to
>> >>>>>>> use) or by modifying algae to be more accessible; looking at the
>> >>>>>>> response functions, I suspect it would be reasonably possible to
>> >>>>>>> modify it.  (Modifying algae is my preference.)
>> >>>>>>> * Use viridis (which we may then have to ship if we have older
>> >>>>>>> versions of matplotlib to support)
>> >>>>>>>
>> >>>>>>> -Matt
>> >>>>>>> _______________________________________________
>> >>>>>>> yt-dev mailing list
>> >>>>>>> yt-dev at lists.spacepope.org
>> >>>>>>> http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
>> >>>>>>
>> >>>>>> _______________________________________________
>> >>>>>> yt-dev mailing list
>> >>>>>> yt-dev at lists.spacepope.org
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>> >>>>>
>> >>>>>
>> >>>>>
>> >>>>> _______________________________________________
>> >>>>> yt-dev mailing list
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>> >>>>> http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
>> >>>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> --
>> >>>> Erik Schnetter <schnetter at gmail.com>
>> >>>> http://www.perimeterinstitute.ca/personal/eschnetter/
>> >>>> _______________________________________________
>> >>>> yt-dev mailing list
>> >>>> yt-dev at lists.spacepope.org
>> >>>> http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
>> >>>
>> >>>
>> >>>
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