First, the entire globe is drawn with a light color. Then, the front-facing polygons are drawn on top with a darker color. Compare to this alternative approach.
forked from mbostock's block: See-Through Globe
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<meta charset="utf-8">
<style>
body {
background: #fcfcfa;
}
</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()
.scale(width / 2.1)
.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)
.context(context);
d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/world-110m.json", function(error, topo) {
if (error) throw error;
var land = topojson.feature(topo, topo.objects.land),
grid = graticule();
d3.timer(function() {
context.clearRect(0, 0, width, height);
projection.rotate([speed * (Date.now() - start), -15]).clipAngle(90);
context.beginPath();
path(sphere);
context.lineWidth = 3;
context.strokeStyle = "#000";
context.stroke();
context.fillStyle = "#fff";
context.fill();
projection.clipAngle(180);
context.beginPath();
path(land);
context.fillStyle = "#dadac4";
context.fill();
context.beginPath();
path(grid);
context.lineWidth = .5;
context.strokeStyle = "rgba(119,119,119,.5)";
context.stroke();
projection.clipAngle(90);
context.beginPath();
path(land);
context.fillStyle = "#737368";
context.fill();
context.lineWidth = .5;
context.strokeStyle = "#000";
context.stroke();
});
});
d3.select(self.frameElement).style("height", height + "px");
</script>
https://d3js.org/d3.v3.min.js
https://d3js.org/topojson.v1.min.js