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Mike Bostock
Visualization toolmaker. Founder @observablehq. Creator @d3. Former @nytgraphics. Pronounced BOSS-tock.
Published
Edited
Nov 21, 2019
1 fork
18 stars
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ΔE = sqrt(
(ΔLp / (k_L * S_L)) ** 2
+ (ΔCp / (k_C * S_C)) ** 2
+ (ΔHp / (k_H * S_H)) ** 2
+ R_T
* (ΔCp / (k_C * S_C))
* (ΔHp / (k_H * S_H))
)
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C_1 = sqrt(a_1 ** 2 + b_1 ** 2)
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C_2 = sqrt(a_2 ** 2 + b_2 ** 2)
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ΔLp = L_2 - L_1
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L_ = (L_1 + L_2) / 2
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C_ = (C_1 + C_2) / 2
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ap_1 = a_1 + (a_1 / 2) * (1 - sqrt(C_ ** 7 / (C_ ** 7 + 25 ** 7)))
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ap_2 = a_2 + (a_2 / 2) * (1 - sqrt(C_ ** 7 / (C_ ** 7 + 25 ** 7)))
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Cp_ = (Cp_1 + Cp_2) / 2
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ΔCp = Cp_2 - Cp_1
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Cp_1 = sqrt(ap_1 ** 2 + b_1 ** 2)
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Cp_2 = sqrt(ap_2 ** 2 + b_2 ** 2)
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hp_1 = (atan2(b_1, ap_1) + 360) % 360
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hp_2 = (atan2(b_2, ap_2) + 360) % 360
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Δhp = abs(hp_1 - hp_2) <= 180 ? hp_2 - hp_1
: hp_2 <= hp_1 ? hp_2 - hp_1 + 360
: hp_2 - hp_1 - 360
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ΔHp = 2 * sqrt(Cp_1 * Cp_2) * sin(Δhp / 2)
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Hp_ = abs(hp_1 - hp_2) <= 180 ? (hp_1 + hp_2) / 2
: hp_1 + hp_2 < 360 ? (hp_1 + hp_2 + 360) / 2
: (hp_1 + hp_2 - 360) / 2
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T = 1
- 0.17 * cos(Hp_ - 30)
+ 0.24 * cos(2 * Hp_)
+ 0.32 * cos(3 * Hp_ + 6)
- 0.20 * cos(4 * Hp_ - 63)
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S_L = 1 + 0.015 * ((L_ - 50) ** 2) / sqrt(20 + (L_ - 50) ** 2)
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S_C = 1 + 0.045 * Cp_
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S_H = 1 + 0.015 * Cp_ * T
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R_T = -2
* sqrt((Cp_ ** 7) / (Cp_ ** 7 + 25 ** 7))
* sin(60 * exp(-(((Hp_ - 275) / 25) ** 2)))
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sin = x => Math.sin(x * Math.PI / 180)
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cos = x => Math.cos(x * Math.PI / 180)
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atan2 = (y, x) => Math.atan2(y, x) * 180 / Math.PI
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sqrt = Math.sqrt
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exp = Math.exp
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abs = Math.abs
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color = value => {
const form = html`<form><input name=color type=color value=${value}>`;
form.color.oninput = () => form.value = d3.lab(form.color.value);
form.value = d3.lab(value);
return form;
}
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d3 = require("d3-color@1")
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Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
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