See also this histogram of an Irwin–Hall distribution.
<!DOCTYPE html>
<meta charset="utf-8">
<style>
svg {
font: 10px sans-serif;
}
rect {
fill: steelblue;
}
.axis path, .axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
var margin = {top: 10, right: 20, bottom: 20, left: 60},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var x = d3.scale.linear()
.range([0, width]);
var y = d3.scale.linear()
.range([height, 0]);
d3.csv("income.csv", function(error, bins) {
if (error) throw error;
// Coerce types.
bins.forEach(function(bin) {
bin.Income = +bin.Income;
bin.People = +bin.People;
});
// Normalize each bin to so that height = quantity/width;
// see //en.wikipedia.org/wiki/Histogram#Examples
for (var i = 1, n = bins.length, bin; i < n; i++) {
bin = bins[i];
bin.offset = bins[i - 1].Income;
bin.width = bin.Income - bin.offset;
bin.height = bin.People / bin.width;
}
// Drop the first bin, since it's incorporated into the next.
bins.shift();
// Set the scale domain.
x.domain([0, d3.max(bins.map(function(d) { return d.offset + d.width; }))]);
y.domain([0, d3.max(bins.map(function(d) { return d.height; }))]);
// Add the bins.
svg.selectAll(".bin")
.data(bins)
.enter().append("rect")
.attr("class", "bin")
.attr("x", function(d) { return x(d.offset); })
.attr("width", function(d) { return x(d.width) - 1; })
.attr("y", function(d) { return y(d.height); })
.attr("height", function(d) { return height - y(d.height); });
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(d3.svg.axis()
.scale(x)
.orient("bottom"));
svg.append("g")
.attr("class", "y axis")
.call(d3.svg.axis()
.scale(y)
.orient("left"));
});
</script>
Income,People
0,245981
8.8,150444
30,126063
49.9,123519
70,115029
90.7,277149
109.1,355768
130,324246
150.3,353239
170.2,396008
190,396725
210,398640
230.1,401932
250,416079
270,412727
289.8,385192
309.7,343178
329.7,293707
349.6,239982
369.7,201557
389.3,165132
442.3,442075
543.4,196526
679.9,146784
883.9,48600
1555,44644