Polar Area Small Multiples

A small multiples visualization of polar area charts showing the breakdown of religions for the largest 5 countries. This is example 30 from the screencast Splitting Charts.

Data from Pew Research Center Global Religious Landscape data set
Uses d3-legend
Uses nested selections.

forked from curran's block: Polar Area Diagram

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>D3 Example</title>
    <script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/d3-legend/1.1.0/d3-legend.js"></script>
    <link href='https://fonts.googleapis.com/css?family=Open+Sans' rel='stylesheet' type='text/css'>
    <style>
    
      .axis text {
        font-family: 'Open Sans', sans-serif;
        font-size: 20pt;
      }

.axis path, .axis line {
        fill: none;
        stroke: #000;
        shape-rendering: crispEdges;
      }

.color-legend text {
        font-family: 'Open Sans', sans-serif;
        font-size: 20pt;
      }

</style>
  </head>
  <body>
    <script>

var outerWidth = 960;
      var outerHeight = 500;
      var margin = { left: 79, top: 50, right: 297, bottom: 152 };
      var radiusMax = 143;

var xColumn = "country";
      var colorColumn = "religion";
      var radiusColumn = "population";

var innerWidth  = outerWidth  - margin.left - margin.right;
      var innerHeight = outerHeight - margin.top  - margin.bottom;

var svg = d3.select("body").append("svg")
        .attr("width",  outerWidth)
        .attr("height", outerHeight);
      var g = svg.append("g")
        .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
      var xAxisG = g.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + innerHeight + ")");

var colorLegendG = svg.append("g")
        .attr("class", "color-legend")
        .attr("transform", "translate(714, 40)");

var xScale = d3.scale.ordinal().rangePoints([0, innerWidth]);
      var radiusScale = d3.scale.sqrt().range([0, radiusMax]);
      var colorScale = d3.scale.category10();

var xAxis = d3.svg.axis().scale(xScale).orient("bottom")
        .outerTickSize(0);

var pie = d3.layout.pie();
      var arc = d3.svg.arc();

var colorLegend = d3.legend.color()
        .scale(colorScale)
        .shapePadding(3)
        .shapeWidth(40)
        .shapeHeight(40)
        .labelOffset(4);

function render(data){

var nested = d3.nest()
          .key(function (d){ return d[xColumn]; })
          .entries(data)

xScale.domain(nested.map( function (d){ return d.key; }));
        radiusScale.domain([
          0,
          d3.max(nested, function (xEntry){
            return d3.max(xEntry.values, function (d){
              return d[radiusColumn];
            });
          })
        ]);
        colorScale.domain(nested[0].values.map(function (d){
          return d[colorColumn];
        }));

pie.value(function (){ return 1; });
        arc.outerRadius(function(d) { 
          return radiusScale(d.data[radiusColumn]);
        });

var pies = g.selectAll(".pie").data(nested);
        pies.enter().append("g").attr("class", "pie");
        pies.attr("transform", function (d){
          var x = xScale(d.key);
          return "translate(" + x + "," + innerHeight / 2 + ")";
        });
        pies.exit().remove();

var slices = pies.selectAll("path").data(function (d){
          return pie(d.values);
        });

slices.enter().append("path");
        slices
          .attr("d", arc)
          .attr("fill", function (d){ return colorScale(d.data[colorColumn]); });
        slices.exit().remove();

xAxisG.call(xAxis);
        colorLegendG.call(colorLegend);
      }

function type(d){
        d.name = "World";
        d.population = +d.population;
        return d;
      }

d3.csv("religionByCountryTop5.csv", type, render);

</script>
  </body>
</html>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js

https://cdnjs.cloudflare.com/ajax/libs/d3-legend/1.1.0/d3-legend.js