map = {
const context = DOM.context2d(width, height);
const ratio = width / height
const [w, h] = (ratio > 1) ? [30, 30 / ratio] : [30 * ratio, 30]
const coordinates = [[-w, -h], [-w, h], [w, -h], [w, h]]
projection.fitExtent([[0,0],[width,height]],{type: 'MultiPoint', coordinates})
projection.rotate([0,-90,0])
projection.reflectX(true)
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(night), context.fillStyle = "rgba(0,0,255,0.3)", context.fill();
context.beginPath(), path(sphere), context.strokeStyle = "#000", context.stroke();
return context.canvas;
}
height = width * 2
// height = {
// const [[x0, y0], [x1, y1]] = d3.geoPath(projection.fitWidth(width, sphere)).bounds(sphere);
// const dy = Math.ceil(y1 - y0), l = Math.min(Math.ceil(x1 - x0), dy);
// projection.scale(projection.scale() * (l - 1) / l).precision(0.2);
// return dy;
// }
projection = d3.geoEquirectangular()
sun = {
const now = new Date;
const day = new Date(+now).setUTCHours(0, 0, 0, 0);
const t = solar.century(now);
const longitude = (day - now) / 864e5 * 360 - 180;
return [longitude - solar.equationOfTime(t) / 4, solar.declination(t)];
}
night = d3.geoCircle()
.radius(90)
.center(antipode(sun))
()
antipode = ([longitude, latitude]) => [longitude + 180, -latitude]
sphere = ({type: "Sphere"})
graticule = d3.geoGraticule10()
land = topojson.feature(world, world.objects.land)
world = fetch("https://cdn.jsdelivr.net/npm/world-atlas@2/land-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")
Purpose-built for displays of data
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.
