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Undersea Cables II
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| body { | |
| background: #fcfcfa; | |
| } | |
| </style> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script src="//d3js.org/d3.geo.projection.v0.min.js"></script> | |
| <script src="//d3js.org/topojson.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 960, | |
| speed = 1e-2; | |
| var sphere = {type: "Sphere"}; | |
| var projection = d3.geo.orthographic() | |
| .clipAngle(90) | |
| .translate([width / 2, height / 2]) | |
| .precision(.5); | |
| var graticule = d3.geo.graticule(); | |
| var canvas = d3.select("body").append("canvas") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var context = canvas.node().getContext("2d"); | |
| var path = d3.geo.path() | |
| .projection(projection) | |
| .pointRadius(1.5) | |
| .context(context); | |
| d3.json("topo.json", function(error, topo) { | |
| if (error) throw error; | |
| var land = topojson.feature(topo, topo.objects.land), | |
| borders = topojson.mesh(topo, topo.objects.countries, function(a, b) { return a !== b; }), | |
| cables = topojson.feature(topo, topo.objects.cables), | |
| landings = topojson.feature(topo, topo.objects.landings), | |
| grid = graticule(); | |
| cables.features.forEach(function(cable) { | |
| if (cable.geometry.type === "LineString") resample(cable.geometry.coordinates); | |
| else cable.geometry.coordinates.forEach(resample); | |
| }); | |
| d3.timer(function(elapsed) { | |
| projection.rotate([speed * elapsed, -15]); | |
| context.clearRect(0, 0, width, height); | |
| projection.scale(width / 2.2).clipAngle(90); | |
| context.beginPath(); | |
| path(sphere); | |
| context.fillStyle = "#fff"; | |
| context.fill(); | |
| context.beginPath(); | |
| path(grid); | |
| context.lineWidth = .5; | |
| context.strokeStyle = "#ddd"; | |
| context.stroke(); | |
| context.beginPath(); | |
| path(land); | |
| context.fillStyle = "#ddd"; | |
| context.fill(); | |
| context.beginPath(); | |
| path(borders); | |
| context.lineWidth = 1; | |
| context.strokeStyle = "#fff"; | |
| context.stroke(); | |
| projection.scale(width / 2.1).clipAngle(107); | |
| context.beginPath(); | |
| path(cables); | |
| context.lineWidth = .5; | |
| context.strokeStyle = "#333"; | |
| context.stroke(); | |
| context.beginPath(); | |
| path(landings); | |
| context.fillStyle = "#555"; | |
| context.fill(); | |
| projection.scale(width / 2.2).clipAngle(90); | |
| context.beginPath(); | |
| path(sphere); | |
| context.lineWidth = 1.5; | |
| context.strokeStyle = "#000"; | |
| context.stroke(); | |
| }); | |
| }); | |
| // Takes a sparse line string that assumes Cartesian interpolation in spherical | |
| // coordinates and inserts interstitial points for greater accuracy when | |
| // rendering with D3, which assumes spherical interpolation. | |
| function resample(coordinates) { | |
| var i = 0, | |
| j = -1, | |
| n = coordinates.length, | |
| source = coordinates.slice(), | |
| p0, x0, y0, | |
| p1 = coordinates[0], x1 = p1[0], y1 = p1[1], | |
| dx, dy, d2, | |
| m2 = 10; // squared minimum angular distance | |
| while (++i < n) { | |
| p0 = p1, x0 = x1, y0 = y1; | |
| p1 = source[i], x1 = p1[0], y1 = p1[1]; | |
| dx = x1 - x0, dy = y1 - y0, d2 = dx * dx + dy * dy; | |
| coordinates[++j] = p0; | |
| if (d2 > m2) for (var k = 1, m = Math.ceil(Math.sqrt(d2 / m2)); k < m; ++k) { | |
| coordinates[++j] = [x0 + dx * k / m, y0 + dy * k / m]; | |
| } | |
| } | |
| coordinates[++j] = p1; | |
| coordinates.length = j + 1; | |
| } | |
| d3.select(self.frameElement).style("height", height + "px"); | |
| </script> |
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