Spiral Stress Test

Stress test for antemeridian cutting!

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.foreground {
  fill: none;
  stroke: #333;
  stroke-width: 1.5px;
}

.graticule {
  fill: none;
  stroke: #000;
  stroke-width: .5px;
}

.graticule:nth-child(2n) {
  stroke-dasharray: 2,2;
}

.land {
  fill: #eee;
  stroke: #000;
  stroke-width: .5px;
}

.spiral {
  fill: red;
  fill-opacity: .5;
  stroke: #000;
  stroke-width: .5px;
}

.boundary {
  fill: none;
  stroke: #ccc;
}

</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script>

var width = 960,
    height = 500;

var projection = d3.geo.equirectangular().translate([width / 2 - .5, height / 2 - .5]).scale(150),
    path = d3.geo.path().projection(projection);

var graticule = d3.geo.graticule();

var svg = d3.select("body").append("svg")
    .datum({x: 0, y: 0})
    .attr("width", width)
    .attr("height", height)
    .call(d3.behavior.drag()
      .origin(Object)
      .on("drag", function(d) {
        d.x = d3.event.x;
        d.y = d3.event.y;
        projection.rotate([d.x, -d.y]);
        svg.selectAll("path").attr("d", path);
      }));

svg.selectAll(".graticule")
    .data(graticule.lines)
  .enter().append("path")
    .attr("class", "graticule")
    .attr("d", path);

var n = 1e3, dy = 5;

var spiral = d3.range(0, 1 + 1 / n, 1 / n).map(function(t) {
  return [(360 * 10 * t) % 360 - 180, -90 + dy + (90 - dy) * 2 * t];
}).concat(d3.range(1, 0, -1 / n).map(function(t) {
  return [(360 * 10 * t) % 360 - 180, -90 + (90 - dy) * 2 * t];
}));
spiral.push(spiral[0]);

svg.append("path")
    .datum({type: "Polygon", coordinates: [spiral]})
    .attr("class", "spiral")
    .attr("d", path);

d3.json("/mbostock/3682676/example/readme-boundaries.json", function(err, collection) {
  svg.insert("g", ".graticule")
      .attr("class", "boundary")
    .selectAll("path")
      .data(collection.geometries)
    .enter().append("path")
      .attr("d", path);
    });

d3.json("/mbostock/3682676/example/readme-land.json", function(err, collection) {
  svg.insert("g", ".graticule,.boundary")
      .attr("class", "land")
    .selectAll("path")
      .data(collection.geometries)
    .enter().append("path")
      .attr("d", path);
});

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

Changed ajax call from /d/3682676/readme-boundaries.json to /mbostock/3682676/example/readme-boundaries.json.

Changed ajax call from /d/3682676/readme-land.json to /mbostock/3682676/example/readme-land.json.

https://d3js.org/d3.v3.min.js