Global Migration in 2015 - new data

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README.md

A Chord Diagram visualization of global migration data from 2015. Data is from the United Nations International Migrant Stock Database. Inspired by:

• d3-chord
• Mike Bostock’s Block - Chord Diagram
• Nadieh Bremer’s Block - Chord diagram 2014 - End result

forked from curran's block: Global Migration in 2015

commuterOut3.csv

hierarchy.json

{
  "data": {
    "id": "WORLD"
  },
  "children": [
    {
      "data": {
        "id": "Asia"
      },
      "children": [
        {
          "data": {
            "id": "Southern Asia"
          },
          "children": [
            {
              "data": {
                "id": "Afghanistan"
              }
            },
            {
              "data": {
                "id": "Bangladesh"
              }
            },
            {
              "data": {
                "id": "Bhutan"
              }
            },
            {
              "data": {
                "id": "India"
              }
            },
            {
              "data": {
                "id": "Iran (Islamic Republic of)"
              }
            },
            {
              "data": {
                "id": "Maldives"
              }
            },
            {
              "data": {
                "id": "Nepal"
              }
            },
            {
              "data": {
                "id": "Pakistan"
              }
            },
            {
              "data": {
                "id": "Sri Lanka"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Western Asia"
          },
          "children": [
            {
              "data": {
                "id": "Armenia"
              }
            },
            {
              "data": {
                "id": "Azerbaijan"
              }
            },
            {
              "data": {
                "id": "Bahrain"
              }
            },
            {
              "data": {
                "id": "Cyprus"
              }
            },
            {
              "data": {
                "id": "Georgia"
              }
            },
            {
              "data": {
                "id": "Iraq"
              }
            },
            {
              "data": {
                "id": "Israel"
              }
            },
            {
              "data": {
                "id": "Jordan"
              }
            },
            {
              "data": {
                "id": "Kuwait"
              }
            },
            {
              "data": {
                "id": "Lebanon"
              }
            },
            {
              "data": {
                "id": "Oman"
              }
            },
            {
              "data": {
                "id": "Qatar"
              }
            },
            {
              "data": {
                "id": "Saudi Arabia"
              }
            },
            {
              "data": {
                "id": "State of Palestine"
              }
            },
            {
              "data": {
                "id": "Syrian Arab Republic"
              }
            },
            {
              "data": {
                "id": "Turkey"
              }
            },
            {
              "data": {
                "id": "United Arab Emirates"
              }
            },
            {
              "data": {
                "id": "Yemen"
              }
            }
          ]
        },
        {
          "data": {
            "id": "South-Eastern Asia"
          },
          "children": [
            {
              "data": {
                "id": "Brunei Darussalam"
              }
            },
            {
              "data": {
                "id": "Cambodia"
              }
            },
            {
              "data": {
                "id": "Indonesia"
              }
            },
            {
              "data": {
                "id": "Lao People's Democratic Republic"
              }
            },
            {
              "data": {
                "id": "Malaysia"
              }
            },
            {
              "data": {
                "id": "Myanmar"
              }
            },
            {
              "data": {
                "id": "Philippines"
              }
            },
            {
              "data": {
                "id": "Singapore"
              }
            },
            {
              "data": {
                "id": "Thailand"
              }
            },
            {
              "data": {
                "id": "Timor-Leste"
              }
            },
            {
              "data": {
                "id": "Viet Nam"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Eastern Asia"
          },
          "children": [
            {
              "data": {
                "id": "China"
              }
            },
            {
              "data": {
                "id": "China, Hong Kong Special Administrative Region"
              }
            },
            {
              "data": {
                "id": "China, Macao Special Administrative Region"
              }
            },
            {
              "data": {
                "id": "Democratic People's Republic of Korea"
              }
            },
            {
              "data": {
                "id": "Japan"
              }
            },
            {
              "data": {
                "id": "Mongolia"
              }
            },
            {
              "data": {
                "id": "Republic of Korea"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Central Asia"
          },
          "children": [
            {
              "data": {
                "id": "Kazakhstan"
              }
            },
            {
              "data": {
                "id": "Kyrgyzstan"
              }
            },
            {
              "data": {
                "id": "Tajikistan"
              }
            },
            {
              "data": {
                "id": "Turkmenistan"
              }
            },
            {
              "data": {
                "id": "Uzbekistan"
              }
            }
          ]
        }
      ]
    },
    {
      "data": {
        "id": "Europe"
      },
      "children": [
        {
          "data": {
            "id": "Southern Europe"
          },
          "children": [
            {
              "data": {
                "id": "Albania"
              }
            },
            {
              "data": {
                "id": "Andorra"
              }
            },
            {
              "data": {
                "id": "Bosnia and Herzegovina"
              }
            },
            {
              "data": {
                "id": "Croatia"
              }
            },
            {
              "data": {
                "id": "Gibraltar"
              }
            },
            {
              "data": {
                "id": "Greece"
              }
            },
            {
              "data": {
                "id": "Holy See"
              }
            },
            {
              "data": {
                "id": "Italy"
              }
            },
            {
              "data": {
                "id": "Malta"
              }
            },
            {
              "data": {
                "id": "Montenegro"
              }
            },
            {
              "data": {
                "id": "Portugal"
              }
            },
            {
              "data": {
                "id": "San Marino"
              }
            },
            {
              "data": {
                "id": "Serbia"
              }
            },
            {
              "data": {
                "id": "Slovenia"
              }
            },
            {
              "data": {
                "id": "Spain"
              }
            },
            {
              "data": {
                "id": "The former Yugoslav Republic of Macedonia"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Western Europe"
          },
          "children": [
            {
              "data": {
                "id": "Austria"
              }
            },
            {
              "data": {
                "id": "Belgium"
              }
            },
            {
              "data": {
                "id": "France"
              }
            },
            {
              "data": {
                "id": "Germany"
              }
            },
            {
              "data": {
                "id": "Liechtenstein"
              }
            },
            {
              "data": {
                "id": "Luxembourg"
              }
            },
            {
              "data": {
                "id": "Monaco"
              }
            },
            {
              "data": {
                "id": "Netherlands"
              }
            },
            {
              "data": {
                "id": "Switzerland"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Eastern Europe"
          },
          "children": [
            {
              "data": {
                "id": "Belarus"
              }
            },
            {
              "data": {
                "id": "Bulgaria"
              }
            },
            {
              "data": {
                "id": "Czech Republic"
              }
            },
            {
              "data": {
                "id": "Hungary"
              }
            },
            {
              "data": {
                "id": "Poland"
              }
            },
            {
              "data": {
                "id": "Republic of Moldova"
              }
            },
            {
              "data": {
                "id": "Romania"
              }
            },
            {
              "data": {
                "id": "Russian Federation"
              }
            },
            {
              "data": {
                "id": "Slovakia"
              }
            },
            {
              "data": {
                "id": "Ukraine"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Northern Europe"
          },
          "children": [
            {
              "data": {
                "id": "Channel Islands"
              }
            },
            {
              "data": {
                "id": "Denmark"
              }
            },
            {
              "data": {
                "id": "Estonia"
              }
            },
            {
              "data": {
                "id": "Faeroe Islands"
              }
            },
            {
              "data": {
                "id": "Finland"
              }
            },
            {
              "data": {
                "id": "Iceland"
              }
            },
            {
              "data": {
                "id": "Ireland"
              }
            },
            {
              "data": {
                "id": "Isle of Man"
              }
            },
            {
              "data": {
                "id": "Latvia"
              }
            },
            {
              "data": {
                "id": "Lithuania"
              }
            },
            {
              "data": {
                "id": "Norway"
              }
            },
            {
              "data": {
                "id": "Sweden"
              }
            },
            {
              "data": {
                "id": "United Kingdom of Great Britain and Northern Ireland"
              }
            }
          ]
        }
      ]
    },
    {
      "data": {
        "id": "Africa"
      },
      "children": [
        {
          "data": {
            "id": "Northern Africa"
          },
          "children": [
            {
              "data": {
                "id": "Algeria"
              }
            },
            {
              "data": {
                "id": "Egypt"
              }
            },
            {
              "data": {
                "id": "Libya"
              }
            },
            {
              "data": {
                "id": "Morocco"
              }
            },
            {
              "data": {
                "id": "Sudan"
              }
            },
            {
              "data": {
                "id": "Tunisia"
              }
            },
            {
              "data": {
                "id": "Western Sahara"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Middle Africa"
          },
          "children": [
            {
              "data": {
                "id": "Angola"
              }
            },
            {
              "data": {
                "id": "Cameroon"
              }
            },
            {
              "data": {
                "id": "Central African Republic"
              }
            },
            {
              "data": {
                "id": "Chad"
              }
            },
            {
              "data": {
                "id": "Congo"
              }
            },
            {
              "data": {
                "id": "Democratic Republic of the Congo"
              }
            },
            {
              "data": {
                "id": "Equatorial Guinea"
              }
            },
            {
              "data": {
                "id": "Gabon"
              }
            },
            {
              "data": {
                "id": "Sao Tome and Principe"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Western Africa"
          },
          "children": [
            {
              "data": {
                "id": "Benin"
              }
            },
            {
              "data": {
                "id": "Burkina Faso"
              }
            },
            {
              "data": {
                "id": "Cabo Verde"
              }
            },
            {
              "data": {
                "id": "Côte d'Ivoire"
              }
            },
            {
              "data": {
                "id": "Gambia"
              }
            },
            {
              "data": {
                "id": "Ghana"
              }
            },
            {
              "data": {
                "id": "Guinea"
              }
            },
            {
              "data": {
                "id": "Guinea-Bissau"
              }
            },
            {
              "data": {
                "id": "Liberia"
              }
            },
            {
              "data": {
                "id": "Mali"
              }
            },
            {
              "data": {
                "id": "Mauritania"
              }
            },
            {
              "data": {
                "id": "Niger"
              }
            },
            {
              "data": {
                "id": "Nigeria"
              }
            },
            {
              "data": {
                "id": "Saint Helena"
              }
            },
            {
              "data": {
                "id": "Senegal"
              }
            },
            {
              "data": {
                "id": "Sierra Leone"
              }
            },
            {
              "data": {
                "id": "Togo"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Southern Africa"
          },
          "children": [
            {
              "data": {
                "id": "Botswana"
              }
            },
            {
              "data": {
                "id": "Lesotho"
              }
            },
            {
              "data": {
                "id": "Namibia"
              }
            },
            {
              "data": {
                "id": "South Africa"
              }
            },
            {
              "data": {
                "id": "Swaziland"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Eastern Africa"
          },
          "children": [
            {
              "data": {
                "id": "Burundi"
              }
            },
            {
              "data": {
                "id": "Comoros"
              }
            },
            {
              "data": {
                "id": "Djibouti"
              }
            },
            {
              "data": {
                "id": "Eritrea"
              }
            },
            {
              "data": {
                "id": "Ethiopia"
              }
            },
            {
              "data": {
                "id": "Kenya"
              }
            },
            {
              "data": {
                "id": "Madagascar"
              }
            },
            {
              "data": {
                "id": "Malawi"
              }
            },
            {
              "data": {
                "id": "Mauritius"
              }
            },
            {
              "data": {
                "id": "Mayotte"
              }
            },
            {
              "data": {
                "id": "Mozambique"
              }
            },
            {
              "data": {
                "id": "Réunion"
              }
            },
            {
              "data": {
                "id": "Rwanda"
              }
            },
            {
              "data": {
                "id": "Seychelles"
              }
            },
            {
              "data": {
                "id": "Somalia"
              }
            },
            {
              "data": {
                "id": "South Sudan"
              }
            },
            {
              "data": {
                "id": "Uganda"
              }
            },
            {
              "data": {
                "id": "United Republic of Tanzania"
              }
            },
            {
              "data": {
                "id": "Zambia"
              }
            },
            {
              "data": {
                "id": "Zimbabwe"
              }
            }
          ]
        }
      ]
    },
    {
      "data": {
        "id": "Oceania"
      },
      "children": [
        {
          "data": {
            "id": "Polynesia"
          },
          "children": [
            {
              "data": {
                "id": "American Samoa"
              }
            },
            {
              "data": {
                "id": "Cook Islands"
              }
            },
            {
              "data": {
                "id": "French Polynesia"
              }
            },
            {
              "data": {
                "id": "Niue"
              }
            },
            {
              "data": {
                "id": "Samoa"
              }
            },
            {
              "data": {
                "id": "Tokelau"
              }
            },
            {
              "data": {
                "id": "Tonga"
              }
            },
            {
              "data": {
                "id": "Tuvalu"
              }
            },
            {
              "data": {
                "id": "Wallis and Futuna Islands"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Australia and New Zealand"
          },
          "children": [
            {
              "data": {
                "id": "Australia"
              }
            },
            {
              "data": {
                "id": "New Zealand"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Melanesia"
          },
          "children": [
            {
              "data": {
                "id": "Fiji"
              }
            },
            {
              "data": {
                "id": "New Caledonia"
              }
            },
            {
              "data": {
                "id": "Papua New Guinea"
              }
            },
            {
              "data": {
                "id": "Solomon Islands"
              }
            },
            {
              "data": {
                "id": "Vanuatu"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Micronesia"
          },
          "children": [
            {
              "data": {
                "id": "Guam"
              }
            },
            {
              "data": {
                "id": "Kiribati"
              }
            },
            {
              "data": {
                "id": "Marshall Islands"
              }
            },
            {
              "data": {
                "id": "Micronesia (Federated States of)"
              }
            },
            {
              "data": {
                "id": "Nauru"
              }
            },
            {
              "data": {
                "id": "Northern Mariana Islands"
              }
            },
            {
              "data": {
                "id": "Palau"
              }
            }
          ]
        }
      ]
    },
    {
      "data": {
        "id": "Latin America and the Caribbean"
      },
      "children": [
        {
          "data": {
            "id": "Caribbean"
          },
          "children": [
            {
              "data": {
                "id": "Anguilla"
              }
            },
            {
              "data": {
                "id": "Antigua and Barbuda"
              }
            },
            {
              "data": {
                "id": "Aruba"
              }
            },
            {
              "data": {
                "id": "Bahamas"
              }
            },
            {
              "data": {
                "id": "Barbados"
              }
            },
            {
              "data": {
                "id": "British Virgin Islands"
              }
            },
            {
              "data": {
                "id": "Bonaire, Sint Eustatius and Saba"
              }
            },
            {
              "data": {
                "id": "Cayman Islands"
              }
            },
            {
              "data": {
                "id": "Cuba"
              }
            },
            {
              "data": {
                "id": "Curaçao"
              }
            },
            {
              "data": {
                "id": "Dominica"
              }
            },
            {
              "data": {
                "id": "Dominican Republic"
              }
            },
            {
              "data": {
                "id": "Grenada"
              }
            },
            {
              "data": {
                "id": "Guadeloupe"
              }
            },
            {
              "data": {
                "id": "Haiti"
              }
            },
            {
              "data": {
                "id": "Jamaica"
              }
            },
            {
              "data": {
                "id": "Martinique"
              }
            },
            {
              "data": {
                "id": "Montserrat"
              }
            },
            {
              "data": {
                "id": "Puerto Rico"
              }
            },
            {
              "data": {
                "id": "Saint Kitts and Nevis"
              }
            },
            {
              "data": {
                "id": "Saint Lucia"
              }
            },
            {
              "data": {
                "id": "Saint Vincent and the Grenadines"
              }
            },
            {
              "data": {
                "id": "Sint Maarten (Dutch part)"
              }
            },
            {
              "data": {
                "id": "Trinidad and Tobago"
              }
            },
            {
              "data": {
                "id": "Turks and Caicos Islands"
              }
            },
            {
              "data": {
                "id": "United States Virgin Islands"
              }
            }
          ]
        },
        {
          "data": {
            "id": "South America"
          },
          "children": [
            {
              "data": {
                "id": "Argentina"
              }
            },
            {
              "data": {
                "id": "Bolivia (Plurinational State of)"
              }
            },
            {
              "data": {
                "id": "Brazil"
              }
            },
            {
              "data": {
                "id": "Chile"
              }
            },
            {
              "data": {
                "id": "Colombia"
              }
            },
            {
              "data": {
                "id": "Ecuador"
              }
            },
            {
              "data": {
                "id": "Falkland Islands (Malvinas)"
              }
            },
            {
              "data": {
                "id": "French Guiana"
              }
            },
            {
              "data": {
                "id": "Guyana"
              }
            },
            {
              "data": {
                "id": "Paraguay"
              }
            },
            {
              "data": {
                "id": "Peru"
              }
            },
            {
              "data": {
                "id": "Suriname"
              }
            },
            {
              "data": {
                "id": "Uruguay"
              }
            },
            {
              "data": {
                "id": "Venezuela (Bolivarian Republic of)"
              }
            }
          ]
        },
        {
          "data": {
            "id": "Central America"
          },
          "children": [
            {
              "data": {
                "id": "Belize"
              }
            },
            {
              "data": {
                "id": "Costa Rica"
              }
            },
            {
              "data": {
                "id": "El Salvador"
              }
            },
            {
              "data": {
                "id": "Guatemala"
              }
            },
            {
              "data": {
                "id": "Honduras"
              }
            },
            {
              "data": {
                "id": "Mexico"
              }
            },
            {
              "data": {
                "id": "Nicaragua"
              }
            },
            {
              "data": {
                "id": "Panama"
              }
            }
          ]
        }
      ]
    },
    {
      "data": {
        "id": "Northern America"
      },
      "children": [
        {
          "data": {
            "id": "Bermuda"
          }
        },
        {
          "data": {
            "id": "Canada"
          }
        },
        {
          "data": {
            "id": "Greenland"
          }
        },
        {
          "data": {
            "id": "Saint Pierre and Miquelon"
          }
        },
        {
          "data": {
            "id": "United States of America"
          }
        }
      ]
    }
  ]
}

index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <script src="//d3js.org/d3.v4.min.js"></script>
    
    <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.0.0-alpha/css/bootstrap.css">
    <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/tether/1.3.2/js/tether.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.0.0-alpha/js/bootstrap.min.js"></script>

  </head>
  <body>
    <script>

      // Configuration parameters.
      var width = 960,
          height = 960,
          outerPadding = 150,
          labelPadding = 5,
          chordPadding = 0.03,
          arcThickness = 30,
          opacity = 0.5,
          fadedOpacity = 0.01,
          transitionDuration = 300,
          outerRadius = width / 2 - outerPadding,
          innerRadius = outerRadius - arcThickness,
          valueFormat = d3.format(",");

      // DOM Elements.
      var svg = d3.select("body").append("svg")
            .attr("width", width)
            .attr("height", height)
          g = svg.append("g")
            .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")"),
          ribbonsG = g.append("g"),
          groupsG = g.append("g");

      // D3 layouts, shapes and scales.
      var ribbon = d3.ribbon()
            .radius(innerRadius),
          chord = d3.chord()
            .padAngle(chordPadding)
            .sortSubgroups(d3.descending),
          arc = d3.arc()
            .innerRadius(innerRadius)
            .outerRadius(outerRadius),
          color = d3.scaleOrdinal()
            .range(d3.schemeCategory20);
      
      var popoverOptions = {
        html : true,
        template: '<div class="popover" role="tooltip"><div class="popover-arrow"></div><div class="popover-content"></div></div>'
      };

      // Renders the given data as a chord diagram.
      function render(data){

        var matrix = generateMatrix(data),
            chords = chord(matrix);

        color.domain(matrix.map(function (d, i){
          return i;
        }));

        // Render the ribbons.
        ribbonsG.selectAll("path")
            .data(chords)
          .enter().append("path")
            .attr("class", "ribbon")
            .attr("d", ribbon)
            .style("fill", function(d) {
              return color(d.source.index);
            })
            .style("stroke", function(d) {
              return d3.rgb(color(d.source.index)).darker();
            })
            .style("opacity", opacity)
            .on("mouseenter", function(d){
              var src = matrix.names[d.source.index];
              var dest = matrix.names[d.target.index];
              popoverOptions.content = [
                "<strong>" + src +" to " + dest +"</strong>",
                valueFormat(d.target.value),
                "<br><strong>" + dest +" to " + src +"</strong>",
                valueFormat(d.source.value)
              ].join("<br>");
              $(this).popover(popoverOptions);
              $(this).popover("show");
            }) 
            .on("mouseleave", function (d){
              $(this).popover("hide");
            })


        // Scaffold the chord groups.
        var groups = groupsG
          .selectAll("g")
            .data(chords.groups)
          .enter().append("g");

        // Render the chord group arcs.
        groups
          .append("path")
            .attr("class", "arc")
            .attr("d", arc)
            .style("fill", function(group) {
              return color(group.index);
            })
            .style("stroke", function(group) {
              return d3.rgb(color(group.index)).darker();
            })
            .style("opacity", opacity)
            .call(groupHover);

        // Render the chord group labels.
        var angle = d3.local(),
            flip = d3.local();
        groups
          .append("text")
            .each(function(d) {
              angle.set(this, (d.startAngle + d.endAngle) / 2)
              flip.set(this, angle.get(this) > Math.PI);
            })
            .attr("transform", function(d) {
              return [
                "rotate(" + (angle.get(this) / Math.PI * 180 - 90) + ")",
                "translate(" + (outerRadius + labelPadding) + ")",
                flip.get(this) ? "rotate(180)" : ""
              ].join("");
            })
            .attr("text-anchor", function(d) {
              return flip.get(this) ? "end" : "start";
            })
            .text(function(d) {
              return matrix.names[d.index];
            })
            .attr("alignment-baseline", "central")
            .style("font-family", '"Helvetica Neue", Helvetica')
            .style("font-size", "10pt")
            .style("cursor", "default")
            .call(groupHover);
      }

      // Sets up hover interaction to highlight a chord group.
      // Used for both the arcs and the text labels.
      function groupHover(selection){
        selection
          .on("mouseover", function (group){
            g.selectAll(".ribbon")
                .filter(function(ribbon) {
                  return (
                    (ribbon.source.index !== group.index) &&
                    (ribbon.target.index !== group.index)
                  );
                })
              .transition().duration(transitionDuration)
                .style("opacity", fadedOpacity);
          })
          .on("mouseout", function (){
            g.selectAll(".ribbon")
              .transition().duration(transitionDuration)
                .style("opacity", opacity);
          });
      }

      // Generates a matrix (2D array) from the given data, which is expected to
      // have fields {origin, destination, count}. The matrix data structure is required
      // for use with the D3 Chord layout.
      function generateMatrix(data){
        var nameToIndex = {},
            names = [],
            matrix = [],
            n = 0, i, j;
        

        function recordName(name){
          if( !(name in nameToIndex) ){
            nameToIndex[name] = n++;
            names.push(name);
          }
        }

        data.forEach(function (d){
          recordName(d.origin);
          recordName(d.destination);
        });

        for(i = 0; i < n; i++){
          matrix.push([]);
          for(j = 0; j < n; j++){
            matrix[i].push(0);
          }
        }

        data.forEach(function (d){
          i = nameToIndex[d.origin];
          j = nameToIndex[d.destination];
          matrix[j][i] = d.count;
        });

        matrix.names = names;

        return matrix;
      }

      d3.csv("commuterOut3.csv", type, function (dataForCountries){
       // d3.json("hierarchy.json", function (hierarchy){

          // Aggretate country data into regional data.
         // var dataForRegions = aggregate(dataForCountries, hierarchy)
           var filteredData = dataForCountries.filter(function (d){
              return d.count > 100;
           });
            // Reduce clutter by filtering out links with relatively low counts.
           // .filter(function (d){
          //    return d.count > 10000;
          //  });

          render(filteredData);
       // });

      });

      // Parses a single row of the input table.
      function type(d){
        d.count = +d.count;
        return d;
      }

      // Aggregates data from countries to regions.
      function aggregate(data, hierarchy){
        var links = {},
            parent = {},
            descendants = d3.hierarchy(hierarchy).descendants();

        descendants.forEach(function (node){
          if(node.parent){
            parent[node.data.data.id] = node.parent.data.data.id;
          }
        });

        function getLink(origin, destination){
          var key = origin + "|" + destination;
          return (key in links) ? links[key] : (links[key] = {
            origin: origin,
            destination: destination,
            count: 0
          });
        }

        data.forEach(function (d){
          getLink(parent[d.origin], parent[d.destination]).count += d.count;

          //console.log(d.origin + " is in " + parent[d.origin]);
          //console.log(d.destination + " is in " + parent[d.destination]);
        });

        return Object.keys(links).map(function (key){
          return links[key];
        });

      }

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

migration.csv