By changing the scale and clip angle of an orthographic projection, this example creates two concentric spheres to give the appearance of floating landmasses. Inspired by Derek Watkin’s Faux-3D Arcs.
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February 26, 2019 22:34
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Floating Landmasses
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| license: gpl-3.0 | |
| redirect: https://observablehq.com/@mbostock/floating-landmasses |
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| body { | |
| background: #fcfcfa; | |
| } | |
| canvas { | |
| position: absolute; | |
| top: 0; | |
| left: 0; | |
| } | |
| .blur { | |
| -webkit-filter: blur(6px); | |
| filter: blur(6px); | |
| } | |
| </style> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script src="//d3js.org/topojson.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 960, | |
| speed = -1e-2, | |
| start = Date.now(); | |
| var sphere = {type: "Sphere"}; | |
| var projection = d3.geo.orthographic() | |
| .translate([width / 2, height / 2]) | |
| .precision(.5); | |
| var graticule = d3.geo.graticule(); | |
| var canvas1 = d3.select("body").append("canvas"), | |
| canvas2 = d3.select("body").append("canvas").attr("class", "blur"), | |
| canvas3 = d3.select("body").append("canvas"); | |
| d3.selectAll("canvas") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var context1 = canvas1.node().getContext("2d"), | |
| context2 = canvas2.node().getContext("2d"), | |
| context3 = canvas3.node().getContext("2d"); | |
| var path = d3.geo.path() | |
| .projection(projection); | |
| projection.scale(width / 2.3).clipAngle(90); | |
| context1.beginPath(); | |
| path.context(context1)(sphere); | |
| context1.lineWidth = 3; | |
| context1.strokeStyle = "#000"; | |
| context1.stroke(); | |
| context1.beginPath(); | |
| path(sphere); | |
| context1.fillStyle = "#fff"; | |
| context1.fill(); | |
| context2.fillStyle = "rgba(0,0,0,.4)"; | |
| context3.strokeStyle = "rgba(0,0,0,.2)"; | |
| d3.json("/mbostock/raw/4090846/world-110m.json", function(error, topo) { | |
| if (error) throw error; | |
| var land = topojson.feature(topo, topo.objects.land), | |
| grid = graticule(); | |
| d3.timer(function() { | |
| context2.clearRect(0, 0, width, height); | |
| context3.clearRect(0, 0, width, height); | |
| projection.rotate([speed * (Date.now() - start), -15]); | |
| projection.scale(width / 2.3).clipAngle(90); | |
| context2.beginPath(); | |
| path.context(context2)(land); | |
| context2.fill(); | |
| context3.beginPath(); | |
| path.context(context3)(grid); | |
| context3.lineWidth = .5; | |
| context3.stroke(); | |
| projection.scale(width / 2.2).clipAngle(106.3); | |
| context3.beginPath(); | |
| path(land); | |
| context3.fillStyle = "#737368"; | |
| context3.fill(); | |
| projection.scale(width / 2.2).clipAngle(90); | |
| context3.beginPath(); | |
| path(land); | |
| context3.fillStyle = "#dadac4"; | |
| context3.fill(); | |
| }); | |
| }); | |
| d3.select(self.frameElement).style("height", height + "px"); | |
| </script> |
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Hmmm... is it rotating in the correct direction? ;-)
Awesome viz, btw.