Visualization toolmaker. Founder @observablehq. Creator @d3. Former @nytgraphics. Pronounced BOSS-tock.
Published
Edited
Oct 7, 2018
19 forks
36 stars
canvas = {
const context = DOM.context2d(width, height);
const faces = geodesic(subdivision);
function drawTriangle([p0, p1, p2]) {
context.moveTo(...p0);
context.lineTo(...p1);
context.lineTo(...p2);
context.closePath();
}
while (true) {
mutable projection = mutable projection
.rotate([Date.now() / 200, -40]);
const triangles = faces
.map((d, i) => (d = d.map(mutable projection), d.index = i, d))
.filter(d => d3.polygonArea(d) < 0);
context.clearRect(0, 0, width, height);
for (const t of triangles) {
context.beginPath();
drawTriangle(t);
context.fillStyle = d3.interpolateRainbow(faces[t.index][0][0] / 360);
context.fill();
}
context.beginPath();
for (const t of triangles) {
drawTriangle(t);
}
context.stroke();
yield context.canvas;
}
}
mutable projection = d3.geoOrthographic()
.rotate([0, -40])
.translate([width / 2, height / 2])
.fitExtent([[2, 2], [width - 2, height - 2]], sphere)
height = Math.min(width, 640)
sphere = ({type: "Sphere"})
geodesic = {
const φ = 1.618033988749895;
const ρ = 180 / Math.PI;
const vertices = [
[1,φ,0], [-1,φ,0], [1,-φ,0], [-1,-φ,0],
[0,1,φ], [0,-1,φ], [0,1,-φ], [0,-1,-φ],
[φ,0,1], [-φ,0,1], [φ,0,-1], [-φ,0,-1]
];
const faces = [
[0,1,4], [1,9,4], [4,9,5], [5,9,3], [2,3,7],
[3,2,5], [7,10,2], [0,8,10], [0,4,8], [8,2,10],
[8,4,5], [8,5,2], [1,0,6], [11,1,6], [3,9,11],
[6,10,7], [3,11,7], [11,6,7], [6,0,10], [9,1,11]
].map(face => face.map(i => vertices[i]));
function interpolate([x0, y0, z0], [x1, y1, z1], t) {
return [
x0 + t * (x1 - x0),
y0 + t * (y1 - y0),
z0 + t * (z1 - z0)
];
}
function project([x, y, z]) {
return [
Math.atan2(y, x) * ρ,
Math.acos(z / Math.sqrt(x * x + y * y + z * z)) * ρ - 90
];
}
return function(n) {
n = n | 0;
const subfaces = [];
for (const [f0, f1, f2] of faces) {
let f10, f20 = interpolate(f0, f1, 1 / n);
let f11, f21 = interpolate(f0, f2, 1 / n);
subfaces.push([f0, f20, f21]);
for (let i = 1; i < n; ++i) {
f10 = f20, f20 = interpolate(f0, f1, (i + 1) / n);
f11 = f21, f21 = interpolate(f0, f2, (i + 1) / n);
for (let j = 0; j <= i; ++j) {
subfaces.push([
interpolate(f10, f11, j / i),
interpolate(f20, f21, j / (i + 1)),
interpolate(f20, f21, (j + 1) / (i + 1))
]);
}
for (let j = 0; j < i; ++j) {
subfaces.push([
interpolate(f10, f11, j / i),
interpolate(f20, f21, (j + 1) / (i + 1)),
interpolate(f10, f11, (j + 1) / i)
]);
}
}
}
return subfaces.map(f => f.map(project));
};
}
d3 = require("d3@5")
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.