A demonstration of antimeridian cutting using d3.geoInterruptedHomolosine. Just… because.
<!DOCTYPE html>
<meta charset="utf-8">
<canvas width="960" height="500"></canvas>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/d3-geo-projection.v1.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<script>
var canvas = d3.select("canvas"),
context = canvas.node().getContext("2d"),
width = canvas.property("width"),
height = canvas.property("height");
var lambda = d3.scaleLinear()
.domain([0, width])
.range([-180, 180]);
var phi = d3.scaleLinear()
.domain([0, height])
.range([90, -90]);
var projection = d3.geoInterruptedHomolosine()
.translate([width / 2, height / 2]);
var path = d3.geoPath()
.projection(projection)
.context(context);
d3.json("https://d3js.org/world-110m.v1.json", function(error, world) {
if (error) throw error;
var land = topojson.feature(world, world.objects.land),
sphere = {type: "Sphere"},
touch = "ontouchstart" in window;
canvas.on(touch ? "touchmove" : "mousemove", move);
draw();
function move() {
var p = touch ? d3.touches(this)[0] : d3.mouse(this);
projection.rotate([lambda(p[0]), phi(p[1])]), draw();
d3.event.preventDefault();
}
function draw() {
context.clearRect(0, 0, width, height);
context.save();
context.beginPath();
path(sphere);
context.fillStyle = "#fff";
context.fill();
context.clip();
context.beginPath();
path(land);
context.fillStyle = "#000";
context.fill();
context.restore();
context.beginPath();
path(sphere);
context.stroke();
}
});
</script>