map = {
const context = DOM.context2d(width, height);
const path = d3.geoPath(projection, context);
context.beginPath(),
path(graticule),
(context.strokeStyle = "#ccc"),
context.stroke();
context.beginPath(), path(land), (context.fillStyle = "#000"), context.fill();
context.beginPath(),
path({ type: "Polygon", coordinates: [days.map(d => sunAtTime(d))] }),
(context.strokeStyle = "#f00"),
context.stroke();
context.beginPath(),
path({ type: "Point", coordinates: sun }),
(context.fillStyle = "#f00"),
context.fill();
context.beginPath(),
path(sphere),
(context.strokeStyle = "#000"),
context.stroke();
return context.canvas;
}
height = width
projection = d3
.geoOrthographic()
.rotate([-sun[0], -sun[1]])
//.rotate([-sunAtTime(days[110])[0], -sunAtTime(days[110])[1]])
.fitExtent([[1, 1], [width - 1, height - 1]], sphere)
.precision(0.1)
timeOfYear = {
let time = new Date(2019, 0, 1, 12);
let i = 0;
while (true) {
yield Promises.delay(
0,
new Date(time.getTime() + (++i % 365) * 24 * 60 * 60 * 1000)
);
}
}
sun = sunAtTime(timeOfYear)
sunAtTime = function(timeOfYear) {
const time = new Date(timeOfYear);
const day = new Date(+time).setUTCHours(0, 0, 0, 0);
const t = solar.century(time);
const x = ((day - time) / 864e5) * 360 - 180 - solar.equationOfTime(t) / 4;
const y = solar.declination(t);
return [x % 360, y];
}
sphere = ({type: "Sphere"})
graticule = d3.geoGraticule10()
land = topojson.feature(world, world.objects.land)
world = fetch("https://cdn.jsdelivr.net/npm/world-atlas@1/world/50m.json").then(response => response.json())
topojson = require("topojson-client@3")
d3 = require("d3-geo@1")
solar = require("solar-calculator@0.3/dist/solar-calculator.min.js")
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