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 MakerWorld tourHillshaderSimplified 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 draggingOrthographicStreaming ShapefilesFake GlobesPeirce Quincuncial🍃 LeafletU.S.G.S. World Earthquake MapUsing Mapbox GL JSUsing Google Maps
Solar Terminator
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(night), context.fillStyle = "rgba(0,0,255,0.3)", context.fill();
context.beginPath(), path(sphere), context.strokeStyle = "#000", context.stroke();
return context.canvas;
}
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.geoNaturalEarth1()
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.
