mbostock/.block

## .block
license: gpl-3.0
height: 960
border: no
redirect: https://observablehq.com/@d3/d3-chord-diagram

## README.md

      
    Raw
  

              README.md
            
          
    Chord diagrams show directed relationships among a group of entities. Layout inspired by Martin Krzywinski's beautiful work on Circos.

  
## index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font: 10px sans-serif;
}

.group-tick line {
  stroke: #000;
}

.ribbons {
  fill-opacity: 0.67;
}

</style>
<svg width="960" height="960"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var matrix = [
  [11975,  5871, 8916, 2868],
  [ 1951, 10048, 2060, 6171],
  [ 8010, 16145, 8090, 8045],
  [ 1013,   990,  940, 6907]
];

var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height"),
    outerRadius = Math.min(width, height) * 0.5 - 40,
    innerRadius = outerRadius - 30;

var formatValue = d3.formatPrefix(",.0", 1e3);

var chord = d3.chord()
    .padAngle(0.05)
    .sortSubgroups(d3.descending);

var arc = d3.arc()
    .innerRadius(innerRadius)
    .outerRadius(outerRadius);

var ribbon = d3.ribbon()
    .radius(innerRadius);

var color = d3.scaleOrdinal()
    .domain(d3.range(4))
    .range(["#000000", "#FFDD89", "#957244", "#F26223"]);

var g = svg.append("g")
    .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")")
    .datum(chord(matrix));

var group = g.append("g")
    .attr("class", "groups")
  .selectAll("g")
  .data(function(chords) { return chords.groups; })
  .enter().append("g");

group.append("path")
    .style("fill", function(d) { return color(d.index); })
    .style("stroke", function(d) { return d3.rgb(color(d.index)).darker(); })
    .attr("d", arc);

var groupTick = group.selectAll(".group-tick")
  .data(function(d) { return groupTicks(d, 1e3); })
  .enter().append("g")
    .attr("class", "group-tick")
    .attr("transform", function(d) { return "rotate(" + (d.angle * 180 / Math.PI - 90) + ") translate(" + outerRadius + ",0)"; });

groupTick.append("line")
    .attr("x2", 6);

groupTick
  .filter(function(d) { return d.value % 5e3 === 0; })
  .append("text")
    .attr("x", 8)
    .attr("dy", ".35em")
    .attr("transform", function(d) { return d.angle > Math.PI ? "rotate(180) translate(-16)" : null; })
    .style("text-anchor", function(d) { return d.angle > Math.PI ? "end" : null; })
    .text(function(d) { return formatValue(d.value); });

g.append("g")
    .attr("class", "ribbons")
  .selectAll("path")
  .data(function(chords) { return chords; })
  .enter().append("path")
    .attr("d", ribbon)
    .style("fill", function(d) { return color(d.target.index); })
    .style("stroke", function(d) { return d3.rgb(color(d.target.index)).darker(); });

// Returns an array of tick angles and values for a given group and step.
function groupTicks(d, step) {
  var k = (d.endAngle - d.startAngle) / d.value;
  return d3.range(0, d.value, step).map(function(value) {
    return {value: value, angle: value * k + d.startAngle};
  });
}

</script>

## thumbnail.png

      
    Raw
  

              thumbnail.png
	license: gpl-3.0
	height: 960
	border: no
	redirect: https://observablehq.com/@d3/d3-chord-diagram
	<!DOCTYPE html>
	<meta charset="utf-8">
	<style>

	body {
	font: 10px sans-serif;
	}

	.group-tick line {
	stroke: #000;
	}

	.ribbons {
	fill-opacity: 0.67;
	}

	</style>
	<svg width="960" height="960"></svg>
	<script src="https://d3js.org/d3.v4.min.js"></script>
	<script>

	var matrix = [
	[11975, 5871, 8916, 2868],
	[ 1951, 10048, 2060, 6171],
	[ 8010, 16145, 8090, 8045],
	[ 1013, 990, 940, 6907]
	];

	var svg = d3.select("svg"),
	width = +svg.attr("width"),
	height = +svg.attr("height"),
	outerRadius = Math.min(width, height) * 0.5 - 40,
	innerRadius = outerRadius - 30;

	var formatValue = d3.formatPrefix(",.0", 1e3);

	var chord = d3.chord()
	.padAngle(0.05)
	.sortSubgroups(d3.descending);

	var arc = d3.arc()
	.innerRadius(innerRadius)
	.outerRadius(outerRadius);

	var ribbon = d3.ribbon()
	.radius(innerRadius);

	var color = d3.scaleOrdinal()
	.domain(d3.range(4))
	.range(["#000000", "#FFDD89", "#957244", "#F26223"]);

	var g = svg.append("g")
	.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")")
	.datum(chord(matrix));

	var group = g.append("g")
	.attr("class", "groups")
	.selectAll("g")
	.data(function(chords) { return chords.groups; })
	.enter().append("g");

	group.append("path")
	.style("fill", function(d) { return color(d.index); })
	.style("stroke", function(d) { return d3.rgb(color(d.index)).darker(); })
	.attr("d", arc);

	var groupTick = group.selectAll(".group-tick")
	.data(function(d) { return groupTicks(d, 1e3); })
	.enter().append("g")
	.attr("class", "group-tick")
	.attr("transform", function(d) { return "rotate(" + (d.angle * 180 / Math.PI - 90) + ") translate(" + outerRadius + ",0)"; });

	groupTick.append("line")
	.attr("x2", 6);

	groupTick
	.filter(function(d) { return d.value % 5e3 === 0; })
	.append("text")
	.attr("x", 8)
	.attr("dy", ".35em")
	.attr("transform", function(d) { return d.angle > Math.PI ? "rotate(180) translate(-16)" : null; })
	.style("text-anchor", function(d) { return d.angle > Math.PI ? "end" : null; })
	.text(function(d) { return formatValue(d.value); });

	g.append("g")
	.attr("class", "ribbons")
	.selectAll("path")
	.data(function(chords) { return chords; })
	.enter().append("path")
	.attr("d", ribbon)
	.style("fill", function(d) { return color(d.target.index); })
	.style("stroke", function(d) { return d3.rgb(color(d.target.index)).darker(); });

	// Returns an array of tick angles and values for a given group and step.
	function groupTicks(d, step) {
	var k = (d.endAngle - d.startAngle) / d.value;
	return d3.range(0, d.value, step).map(function(value) {
	return {value: value, angle: value * k + d.startAngle};
	});
	}

	</script>