Ch. 7, Fig. 20 - D3.js in Action

This is the code for Chapter 7, Figure 20 from D3.js in Action that demonstrates how to use d3.geo.tile() to create maps using terrain tiles.

<html>
<head>
  <title>D3 in Action Chapter 7 - Example 10</title>
  <meta charset="utf-8" />
<script src="https://d3js.org/d3.geo.projection.v0.min.js" type="text/JavaScript"></script>
<script src="https://d3js.org/queue.v1.min.js" type="text/JavaScript"></script>
<script src="https://d3js.org/colorbrewer.v1.min.js" type="text/JavaScript"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/topojson/1.6.19/topojson.min.js"></script>
<script src="tile.js" type="text/JavaScript"></script>
</head>
<style>
  svg {
    height: 500px;
    width: 500px;
    border: 1px solid gray;
  }
  
  .countries {
    fill: red;
    fill-opacity: .5;
    stroke: black;
    stroke-width: 1px;
  }

</style>
<body>

var width = 500,
    height = 500;
    
  d3.select("svg").append("g").attr("id", "tiles");
  d3.select("svg").append("g").attr("id", "vectors");

queue()
    .defer(d3.json, "world.topojson")
    .defer(d3.csv, "cities.csv")
    .await(function(error, file1, file2) { createMap(file1, file2); });
    
  function createMap(countries1, cities) {
    var countries = topojson.feature(countries1, countries1.objects.countries);

var tile = d3.geo.tile()
    .size([width, height]);

var projection = d3.geo.mercator()
    .scale(120)
    .translate([width / 2, height / 2]);

var center = projection([12, 42]);

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

var zoom = d3.behavior.zoom()
    .scale(projection.scale() * 2 * Math.PI)
    .translate([width - center[0], height - center[1]])
    .on("zoom", redraw);

d3.select("svg").call(zoom);
    redraw();
    
    featureSize = d3.extent(countries.features, function(d) {return geoPath.area(d)});
    countryColor = d3.scale.quantize().domain(featureSize).range(colorbrewer.Reds[7]);

d3.select("#vectors").selectAll("path.countries").data(countries.features)
    .enter()
    .append("path")
    .attr("d", geoPath)
    .attr("class", "countries")
    .style("fill", function(d) {return countryColor(geoPath.area(d))})
    .style("stroke-width", 1)
    .style("stroke", "black")
    .style("opacity", .5)
    .style("display", function(d,i) {return i%2 == 0 ? "none" : "block"})
    
    d3.select("#vectors").selectAll("circle").data(cities)
    .enter()
    .append("circle")
    .style("fill", "black")
    .style("stroke", "white")
    .style("stroke-width", 1)
    .attr("r", 3)
    .attr("cx", function(d) {return projection([d.y,d.x])[0]})
    .attr("cy", function(d) {return projection([d.y,d.x])[1]})

redraw();

function redraw() {
      var tiles = tile
      .scale(zoom.scale())
      .translate(zoom.translate())
      ();
      
      var image = d3.select("#tiles").attr("transform", "scale(" + tiles.scale + ")translate(" + tiles.translate + ")")
    .selectAll("image")
      .data(tiles, function(d) { return d; });

image.exit()
      .remove();

image.enter().append("image")
      .attr("xlink:href", function(d) { return "https://" + ["a", "b", "c", "d"][Math.random() * 4 | 0] + ".tiles.mapbox.com/v3/examples.map-zgrqqx0w/" + d[2] + "/" + d[0] + "/" + d[1] + ".png"; })
      .attr("width", 1)
      .attr("height", 1)
      .attr("x", function(d) { return d[0]; })
      .attr("y", function(d) { return d[1]; });
      
      projection
      .scale(zoom.scale() / 2 / Math.PI)
      .translate(zoom.translate());

d3.selectAll("path.countries")
      .attr("d", geoPath);

d3.selectAll("circle")
    .attr("cx", function(d) {return projection([d.y,d.x])[0]})
    .attr("cy", function(d) {return projection([d.y,d.x])[1]})
      
    }
  }
</script>
  </footer>

</html>

Modified http://d3js.org/colorbrewer.v1.min.js to a secure url

https://d3js.org/d3.geo.projection.v0.min.js

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

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

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js

https://cdnjs.cloudflare.com/ajax/libs/topojson/1.6.19/topojson.min.js