This example illustrates this GeoExamples blog entry. It shows only how to create a base map to be used in the tutorial.
The map is based on this example by Mike Bostock.
<!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;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script src="http://d3js.org/colorbrewer.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("/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);
});
d3.select(self.frameElement).style("height", height + "px");
</script>