Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Histogram with a normal distribution
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<title>Histogram</title>
<script type="text/javascript" src="http://mbostock.github.com/d3/d3.v2.min.js"></script>
<style type="text/css">
body {
margin: 3em;
}
line {
stroke: #ccc;
stroke-width: 1px;
}
circle {
fill: steelblue;
}
</style>
</head>
<body>
<script type="text/javascript">
// data generator
var min = 0,
max = 80000,
stddev = 12000,
bins = 18,
generator = (function() {
var gen = d3.random.normal(max/2, stddev);
return function() {
return ~~Math.max(min, Math.min(gen(), max));
}
}());
var data = d3.range(bins).map(function() { return [] });
// chart
var speed = 800,
w = 300,
h = 300,
bw = w/bins,
r = 3,
padding = 3;
var chart = d3.select('body').append('svg:svg')
.attr('width', w+4)
.attr('height', h+4)
.append('svg:g')
.attr('transform', 'translate(2,2)');
chart.append('svg:line')
.attr('x1', 0)
.attr('x2', w)
.attr('y1', h)
.attr('y2', h);
chart.selectAll('line.v')
.data(d3.range(bins+2))
.enter().append('svg:line')
.attr('class', 'v')
.attr('x1', function(d) { return d * bw })
.attr('x2', function(d) { return d * bw })
.attr('y1', 0)
.attr('y2', h);
var binCols = chart.selectAll('g.bin')
.data(data)
.enter().append('svg:g')
.attr('class', 'bin')
.attr('transform', function(d,i) { return 'translate(' + (i * bw) + ',0)' });
function redraw() {
var dots = binCols.selectAll('circle')
.data(function(d) { return d });
dots.enter().append('svg:circle')
.attr('cx', bw/2)
.attr('cy', 0)
.attr('r', r);
dots.transition()
.duration(speed)
.ease('bounce')
.attr('cy', function(d,i) {
return h - (i * (r*2 + padding) + padding*2)
});
}
var target = 100,
counter = 0,
intervalId = setInterval(function() {
var number = generator();
// console.log(number);
bin = ~~(number / max * bins);
data[bin].push(number);
redraw();
if (++counter > target) {
clearInterval(intervalId);
}
}, speed);
</script>
</body>
</html>
@margulies

This comment has been minimized.

Copy link

margulies commented Apr 6, 2013

Nice work! I was wondering if you could advise on how to include a normally distributed radius 'r' (which I've worked out), but also how to include the individual 'r' values in the stacking height (can't seem to work that out). Many thanks for any suggestions.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.