Make the color-scale compatible with color-blindness

[corradio]

A couple of ideas:

• Use a scale where brightness can be used regardless of hue
• Replace red or green by blue

[AliShug]

I'll second this, I'm only mildly colourblind but the current map is basically unreadable for me. Ideally you would make the colours adjustable, or at least lightness-based.

[nicorikken]

Same issue here, the current color scheme makes the map totally unreadable. I suggest to use the blue to red pattern, like:

[corradio]

Hi there, The problem with the blue-> red pattern is that "green" is in the middle, and it makes sense that we represent low carbon by green. What about a green -> red scale? (say from 505 to 1000 on your scale)

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On Thu, Dec 29, 2016 at 8:06 AM, Nico Rikken ***@***.***> wrote: Same issue here, the current color scheme makes the map totally unreadable. I suggest to use the blue to red pattern, like: <https://camo.githubusercontent.com/5b0d03d764372cfebd7b558f345d8db2e8420609/68747470733a2f2f692e737461636b2e696d6775722e636f6d2f59475a684a2e6a7067> — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#182 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABlEKH3_bKvHvXszXacrUlK8wrf19xGwks5rM1v_gaJpZM4LQLUc> .

[AliShug]

So there's a couple issues with that, namely that in the common green/red colourblindness (which I have) it's green and red that's the issue, and in the scale given I can't see any significant change in lightness from 415-685. In fact everything from 415-640 looks exactly the same. In my opinion, you can use any colours you like, as long as there's a constant and significant gradient in the lightness value.

[corradio]

A quick win is to add an alternative scale with a toggle.
https://twitter.com/ed_hawkins/status/831477129279832064

[corradio]

Good reading:
https://vis4.net/blog/posts/goodbye-redgreen-scales/
Good watching:
https://www.youtube.com/watch?v=xAoljeRJ3lU

Using colorblind-friendly colorscales from https://bids.github.io/colormap/, implemented at https://github.com/d3/d3-scale#interpolateViridis

Viridis Yellow-Blue (scale 1200 - 0)

This one is annoying because Finland looks greener.

Magma Yellow-Red (scale 2000 - 0)

Inferno (scale 2000 - 0)

This one is a bit warmer.

Plasma (scale 2000 - 0)

What do people think? I'm quite in favor of the Magma one as an extra scale for colorblind.