d3 + TopoJSON by almccon

Working with TopoJSON and d3.js projections for mapping geospatial data.

forked from mbostock‘s block: U.S. Counties TopoJSON

index.html

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

path {
  fill: #ccc;
  stroke: #fff;
  stroke-width: .5px;
}

path:hover {
  fill: red;
}

</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 path = d3.geo.path();

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

var url = "https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/us.json"
d3.json(url, function(error, topology) {
  if (error) throw error;
  
  console.log("topojson", topology)
  var geojson = topojson.feature(topology, topology.objects.counties);
  console.log("geojson", geojson)

  svg.selectAll("path")
      .data(geojson.features)
    .enter().append("path")
      .attr("d", path);
});

</script>