48c00b1c3cd9dad09490 by mhkeller

index.html

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

.state {
  fill: #ccc;
}

.county-border {
  fill: none;
  stroke: #fff;
  stroke-width: 1.01px;
  stroke-linejoin: round;
  stroke-linecap: round;
}

</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 = 500;

var projection = d3.geo.conicConformal()
    .parallels([38 + 02 / 60, 39 + 12 / 60])
    .rotate([78 + 30 / 60, 0])
    .scale(8000)
    .translate([0, 0]);

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

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

d3.json("va-counties.json", function(error, topo) {
  var state = topojson.feature(topo, topo.objects.states),
      bounds = path.bounds(state);

  projection
      .translate([width / 2 - (bounds[0][0] + bounds[1][0]) / 2, height / 2 - (bounds[0][1] + bounds[1][1]) / 2]);

  svg.append("path")
      .datum(state)
      .attr("class", "state")
      .attr("d", path);

  svg.append("path")
      .datum(topojson.mesh(topo, topo.objects.counties, function(a, b) { return a !== b; }))
      .attr("class", "county-border")
      .attr("d", path);
});

</script>