Public
Edited
Aug 1, 2023
159 forks
Importers
199 stars
Topographic MappingBubble mapChoroplethAccess to Family planningMD Counties Total Cases MapTendance de la production des déchets en Union EuropéenneAndy's Walgreens COVID-19 Tracker TrackerElection Maps for Incomplete ResultsA better U.S. house election results map?1983 Mayoral Election, Dot density mapsMastodon 🐘Cheat sheet bertinBertin.js: regular squaresWaterlinesNeumorphism Contour Density MapCartographic DoodlesStars and constellationsPlot: Grid choroplethHello Polygon MorphingMapping with pie chartsU.S. Geographic DataHow big are countries... like really!AttitudeB&W ChoroplethWeb Mercator Tile VisibilityMARTINI: Real-Time RTIN Terrain Mesh"Magnifying-Glass" projectionsTissot's indicatrixAntipodal mapMapping gridded data with a Voronoi diagramA Map of Every BuildingUrbano Monti’s Planisphere (1587)Bivariate choroplethDIY HillshadeMapbox Map MakerHillshaderSimplified Earth with curved shapesHexbin mapInner glowNicolosi vs. StereographicData-driven projections: Darwin's worldSatellite ground track visualizerDirection to shoreHello, OpenLayers!U.S. airports VoronoiHello, NYC Geosearch API!Mapbox Fly-ToSpilhaus shoreline mapWalmart’s growthHow well does population density predict U.S. voting outcomes?Drawing maps from geodata with D3 & ObservableHexgrid maps with d3-hexgridTissot's indicatrixWorld airports VoronoiSwiss Elevation Line GraphsVector tilesVersor draggingOrthographicSolar TerminatorStreaming ShapefilesFake GlobesPeirce Quincuncial🍃 LeafletU.S.G.S. World Earthquake MapUsing Mapbox GL JSUsing Google Maps
World tour
canvas = {
// Specify the chart’s dimensions.
const height = Math.min(width, 720); // Observable sets a responsive *width*
// Prepare a canvas.
const dpr = window.devicePixelRatio ?? 1;
const canvas = d3.create("canvas")
.attr("width", dpr * width)
.attr("height", dpr * height)
.style("width", `${width}px`);
const context = canvas.node().getContext("2d");
context.scale(dpr, dpr);
// Create a projection and a path generator.
const projection = d3.geoOrthographic().fitExtent([[10, 10], [width - 10, height - 10]], {type: "Sphere"});
const path = d3.geoPath(projection, context);
const tilt = 20;
function render(country, arc) {
context.clearRect(0, 0, width, height);
context.beginPath(), path(land), context.fillStyle = "#ccc", context.fill();
context.beginPath(), path(country), context.fillStyle = "#f00", context.fill();
context.beginPath(), path(borders), context.strokeStyle = "#fff", context.lineWidth = 0.5, context.stroke();
context.beginPath(), path({type: "Sphere"}), context.strokeStyle = "#000", context.lineWidth = 1.5, context.stroke();
context.beginPath(), path(arc), context.stroke();
return context.canvas;
}
let p1, p2 = [0, 0], r1, r2 = [0, 0, 0];
for (const country of countries) {
mutable name = country.properties.name;
yield render(country);
p1 = p2, p2 = d3.geoCentroid(country);
r1 = r2, r2 = [-p2[0], tilt - p2[1], 0];
const ip = d3.geoInterpolate(p1, p2);
const iv = Versor.interpolateAngles(r1, r2);
await d3.transition()
.duration(1250)
.tween("render", () => t => {
projection.rotate(iv(t));
render(country, {type: "LineString", coordinates: [p1, ip(t)]});
})
.transition()
.tween("render", () => t => {
render(country, {type: "LineString", coordinates: [ip(t), p2]});
})
.end();
}
}
class Versor {
static fromAngles([l, p, g]) {
l *= Math.PI / 360;
p *= Math.PI / 360;
g *= Math.PI / 360;
const sl = Math.sin(l), cl = Math.cos(l);
const sp = Math.sin(p), cp = Math.cos(p);
const sg = Math.sin(g), cg = Math.cos(g);
return [
cl * cp * cg + sl * sp * sg,
sl * cp * cg - cl * sp * sg,
cl * sp * cg + sl * cp * sg,
cl * cp * sg - sl * sp * cg
];
}
static toAngles([a, b, c, d]) {
return [
Math.atan2(2 * (a * b + c * d), 1 - 2 * (b * b + c * c)) * 180 / Math.PI,
Math.asin(Math.max(-1, Math.min(1, 2 * (a * c - d * b)))) * 180 / Math.PI,
Math.atan2(2 * (a * d + b * c), 1 - 2 * (c * c + d * d)) * 180 / Math.PI
];
}
static interpolateAngles(a, b) {
const i = Versor.interpolate(Versor.fromAngles(a), Versor.fromAngles(b));
return t => Versor.toAngles(i(t));
}
static interpolateLinear([a1, b1, c1, d1], [a2, b2, c2, d2]) {
a2 -= a1, b2 -= b1, c2 -= c1, d2 -= d1;
const x = new Array(4);
return t => {
const l = Math.hypot(x[0] = a1 + a2 * t, x[1] = b1 + b2 * t, x[2] = c1 + c2 * t, x[3] = d1 + d2 * t);
x[0] /= l, x[1] /= l, x[2] /= l, x[3] /= l;
return x;
};
}
static interpolate([a1, b1, c1, d1], [a2, b2, c2, d2]) {
let dot = a1 * a2 + b1 * b2 + c1 * c2 + d1 * d2;
if (dot < 0) a2 = -a2, b2 = -b2, c2 = -c2, d2 = -d2, dot = -dot;
if (dot > 0.9995) return Versor.interpolateLinear([a1, b1, c1, d1], [a2, b2, c2, d2]);
const theta0 = Math.acos(Math.max(-1, Math.min(1, dot)));
const x = new Array(4);
const l = Math.hypot(a2 -= a1 * dot, b2 -= b1 * dot, c2 -= c1 * dot, d2 -= d1 * dot);
a2 /= l, b2 /= l, c2 /= l, d2 /= l;
return t => {
const theta = theta0 * t;
const s = Math.sin(theta);
const c = Math.cos(theta);
x[0] = a1 * c + a2 * s;
x[1] = b1 * c + b2 * s;
x[2] = c1 * c + c2 * s;
x[3] = d1 * c + d2 * s;
return x;
};
}
}
mutable name = ""
countries = topojson.feature(world, world.objects.countries).features
borders = topojson.mesh(world, world.objects.countries, (a, b) => a !== b)
land = topojson.feature(world, world.objects.land)
world = FileAttachment("countries-110m.json").json()
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.
