rveciana - simple-path-on-a-map
Simple path on a map

This example illustrates this GeoExamples blog entry. It shows how to draw a path on a map.
<!DOCTYPE html>
<meta charset="utf-8">
<style>

.graticule {
  fill: none;
  stroke: #777;
  stroke-opacity: .5;
  stroke-width: .5px;
}

.land {
  fill: #999;
}

.boundary {
  fill: none;
  stroke: #fff;
  stroke-width: .5px;
}

svg .path {
  fill: none;
  stroke-opacity: .8;
  stroke-dasharray: 3,2;
  stroke: #f44;
}

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script>

var width = 600,
    height = 500;

var projection = d3.geo.mercator()
    .scale(5*(width + 1) / 2 / Math.PI)
    .translate([width / 2, height / 2])
    .rotate([-125, -15, 0])
    .precision(.1);

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

var graticule = d3.geo.graticule();

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

svg.append("path")
    .datum(graticule)
    .attr("class", "graticule")
    .attr("d", path);
d3.json("track.json", function(error, track) {
d3.json("/mbostock/raw/4090846/world-50m.json", function(error, world) {
    svg.insert("path", ".graticule")
      .datum(topojson.feature(world, world.objects.land))
      .attr("class", "land")
      .attr("d", path);

    svg.insert("path", ".graticule")
      .datum(topojson.mesh(world, world.objects.countries, function(a, b) { return a !== b; }))
      .attr("class", "boundary")
      .attr("d", path);
    

    var pathLine = d3.svg.line()
        .interpolate("cardinal")
        .x(function(d) { return projection([d.lon, d.lat])[0]; })
        .y(function(d) { return projection([d.lon, d.lat])[1]; });

    var haiyanPath = svg.append("path")
    .attr("d",pathLine(track))
    .attr("class","path");

});
});


d3.select(self.frameElement).style("height", height + "px");

</script>