Tissot's Indicatrices

Tissot's Indicatrix rendered with D3.

NB:- see Jason's comment about these not being "true" Tissot indicatrices.

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

body {
  margin: 0;
}

.background {
  fill: #bee8ff;
}

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

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

.land {
  fill: #b7db6e;
  stroke: #4f6521;
}

.boundary {
  fill: none;
  stroke: #7b9545;
}

.tissot {
  fill: rgba(255,0,0,0.5);
  stroke: none;
}

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

var radians = Math.PI / 180.0;

var width = window.innerWidth,
    height = window.innerHeight;

var projection = d3.geo.orthographic()
    .scale(Math.min(width,height)*0.45)
    .translate([width / 2 - .5, height / 2 - .5])
    .rotate([-30,-30])
    .clipAngle(90 + 1e-6);

var path = d3.geo.path()
    .projection(projection);

var graticule = d3.geo.graticule().step([30,30]);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

svg.append("path")
    .datum(graticule.outline)
    .attr("class", "background")
    .attr("d", path);

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

svg.append("path")
    .datum(graticule.outline)
    .attr("class", "foreground")
    .attr("d", path);

d3.json("readme-boundaries.json", function(error, collection) {
  svg.insert("path", ".graticule")
      .datum(collection)
      .attr("class", "boundary")
      .attr("d", path);
});

d3.json("readme-land.json", function(error, collection) {
  svg.insert("path", ".graticule,.boundary")
      .datum(collection)
      .attr("class", "land")
      .attr("d", path);
});

var indicatices = d3.merge(d3.range(-180,181,30).map(function(lon) { 
  return d3.range(-60,61,30).map(function(lat) { 
    return d3.geo.circle().origin([ lon, lat ]).angle(7.0)();
  }); 
}));

svg.selectAll("path.tissot")
    .data(indicatices)
  .enter().append("path")
    .attr("class", "tissot")
    .attr("d", path);

</script>

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

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