Add labels to D3 Chord diagram
chord-diagram, d3.js, data-visualization, javascript, label
Solution
Add text elements to display labels. Alternatively, use textPath elements if you want to display text along a path. Two examples of labeled chord diagrams:
- http://mbostock.github.com/d3/talk/20111018/chord.html
- http://bl.ocks.org/1308257
Problem
I'm a rookie programmer, so this one will probably be an easy one for most of you. What lines of code do I need for labels and/or mouse-over text for this Chord diagram? http://mbostock.github.com/d3/ex/chord.html I need it to display the name of the category in the outer strip. When you mouse over, I want to display the exact number and both categories. Something like this: 'A: 5 thing from B'. EDIT: I still can't figure out how to implement it in my code. Can someone fill in my example code an explain what's going on? ``` <!DOCTYPE html> <html> <head> <meta http-equiv="Content-type" content="text/html; charset=utf-8"> <title>Selecties EK 2010</title> <script type="text/javascript" src="d3.v2.js"></script> <link type="text/css" rel="stylesheet" href="ek2010.css"/> </head> <body> <div id="chart"></div> <script type="text/javascript" src="ek2010.js"></script> </body> </html> ``` and ``` // From http://mkweb.bcgsc.ca/circos/guide/tables/ var chord = d3.layout.chord() .padding(.05) .sortSubgroups(d3.descending) .matrix([ [0, 0, 7, 5], [0, 0, 8, 3], [7, 8, 0, 0], [5, 3, 0, 0] ]); var width = 1000, height = 1000, innerRadius = Math.min(width, height) * .3, outerRadius = innerRadius * 1.1; var fill = d3.scale.ordinal() .domain(d3.range(4)) .range(["#000000", "#FFDD89", "#957244", "#F26223"]); var svg = d3.select("#chart") .append("svg") .attr("width", width) .attr("height", height) .append("g") .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")"); svg.append("g") .selectAll("path") .data(chord.groups) .enter().append("path") .style("fill", function(d) { return fill(d.index); }) .style("stroke", function(d) { return fill(d.index); }) .attr("d", d3.svg.arc().innerRadius(innerRadius).outerRadius(outerRadius)) .on("mouseover", fade(.1)) .on("mouseout", fade(1)); var ticks = svg.append("g") .selectAll("g") .data(chord.groups) .enter().append("g") .selectAll("g") .data(groupTicks) .enter().append("g") .attr("transform", function(d) { return "rotate(" + (d.angle * 180 / Math.PI - 90) + ")" + "translate(" + outerRadius + ",0)"; }); ticks.append("line") .attr("x1", 1) .attr("y1", 0) .attr("x2", 5) .attr("y2", 0) .style("stroke", "#000"); ticks.append("text") .attr("x", 8) .attr("dy", ".35em") .attr("text-anchor", function(d) { return d.angle > Math.PI ? "end" : null; }) .attr("transform", function(d) { return d.angle > Math.PI ? "rotate(180)translate(-16)" : null; }) .text(function(d) { return d.label; }); svg.append("g") .attr("class", "chord") .selectAll("path") .data(chord.chords) .enter().append("path") .style("fill", function(d) { return fill(d.target.index); }) .attr("d", d3.svg.chord().radius(innerRadius)) .style("opacity", 1); /** Returns an array of tick angles and labels, given a group. */ function groupTicks(d) { var k = (d.endAngle - d.startAngle) / d.value; return d3.range(0, d.value, 1).map(function(v, i) { return { angle: v * k + d.startAngle, label: i % 5 ? null : v / 1 + " internat." }; }); } /** Returns an event handler for fading a given chord group. */ function fade(opacity) { return function(g, i) { svg.selectAll("g.chord path") .filter(function(d) { return d.source.index != i && d.target.index != i; }) .transition() .style("opacity", opacity); }; } ```