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

This is the code for Chapter 7, Figure 7 from D3.js in Action which ties together several key d3.geo concepts such as drawing bounding boxes with d3.geo.bounds(), rendering points from CSV data, and extended projections from d3.geo.projection (not included in core D3).

label population country x y
San Francisco 750000 USA 37 -122
Fresno 500000 USA 36 -119
Lahore 12500000 Pakistan 31 74
Karachi 13000000 Pakistan 24 67
Rome 2500000 Italy 41 12
Naples 1000000 Italy 40 14
Rio 12300000 Brazil -22 -43
Sao Paolo 12300000 Brazil -23 -46
<html>
<head>
<title>D3 in Action Chapter 7 - Example 2</title>
<meta charset="utf-8" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<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>
</head>
<style>
svg {
height: 500px;
width: 500px;
border: 1px solid gray;
}
.countries {
fill: red;
fill-opacity: .5;
stroke: black;
stroke-width: 1px;
}
</style>
<body>
<div id="viz">
<svg>
</svg>
</div>
<div id="controls" />
</body>
<footer>
<script>
queue()
.defer(d3.json, "world.geojson")
.defer(d3.csv, "cities.csv")
.await(function(error, file1, file2) { createMap(file1, file2); });
function createMap(countries, cities) {
width = 500;
height = 500;
projection = d3.geo.mollweide()
.scale(120)
.translate([width / 2, height / 2])
.center([20,0])
geoPath = d3.geo.path().projection(projection);
featureSize = d3.extent(countries.features, function(d) {return geoPath.area(d)});
countryColor = d3.scale.quantize().domain(featureSize).range(colorbrewer.Reds[7]);
d3.select("svg").selectAll("path").data(countries.features)
.enter()
.append("path")
.attr("d", geoPath)
.style("fill", function(d) {return countryColor(geoPath.area(d))})
.style("stroke-width", 1)
.style("stroke", "black")
.style("opacity", .5)
.on("mouseover", centerBounds)
.on("mouseout", clearCenterBounds)
d3.select("svg").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]})
function centerBounds(d,i) {
thisBounds = geoPath.bounds(d);
thisCenter = geoPath.centroid(d);
d3.select("svg")
.append("rect")
.attr("class", "bbox")
.attr("x", thisBounds[0][0])
.attr("y", thisBounds[0][1])
.attr("width", thisBounds[1][0] - thisBounds[0][0])
.attr("height", thisBounds[1][1] - thisBounds[0][1])
.style("fill", "none")
.style("stroke-dasharray", "5 5")
.style("stroke", "black")
.style("stroke-width", 2)
.style("pointer-events", "none")
d3.select("svg")
.append("circle")
.attr("class", "centroid")
.attr("r", 5)
.attr("cx", thisCenter[0]).attr("cy", thisCenter[1])
.style("pointer-events", "none")
}
function clearCenterBounds() {
d3.selectAll("circle.centroid").remove();
d3.selectAll("rect.bbox").remove();
}
}
</script>
</footer>
</html>
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