Project to Bounding Box

In response to a Stack Overflow question regarding centering a map given a GeoJSON object.

forked from mbostock's block: Project to Bounding Box

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

.feature {
  fill: #ccc;
}

.mesh {
  fill: none;
  stroke: #fff;
  stroke-width: .5px;
  stroke-linejoin: round;
}

.outline {
  fill: #ddd;
  stroke: #000;
  stroke-width: 1.5px;
}

</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 = 500;

var projection = d3.geo.albers();

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

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

d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/us.json", function(error, us) {
  if (error) throw error;

var states = topojson.feature(us, us.objects.states),
      state = states.features.filter(function(d) { return d.id === 34; })[0];

projection
      .scale(1)
      .translate([0, 0]);

var b = path.bounds(state),
      s = .95 / Math.max((b[1][0] - b[0][0]) / width, (b[1][1] - b[0][1]) / height),
      t = [(width - s * (b[1][0] + b[0][0])) / 2, (height - s * (b[1][1] + b[0][1])) / 2];

projection
      .scale(s)
      .translate(t);

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

svg.append("path")
      .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
      .attr("class", "mesh")
      .attr("d", path);

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

</script>

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

https://d3js.org/topojson.v1.min.js