Sunburst Example

A sunburst diagram is a radial space-filling tree visualization, similar in spirit to a treemap. Adjacency, rather than containment, is used to depict hierarchical relationships. The layout is computed using Vega’s partition transform. This example shows the software class hierarchy of the Flare visualization toolkit; node areas are proportional to the file size in bytes of each source code file.

Vega JSON Specification <>

{
  "$schema": "https://vega.github.io/schema/vega/v3.0.json",
  "width": 600,
  "height": 600,
  "padding": 5,
  "autosize": "none",

  "data": [
    {
      "name": "tree",
      "url": "data/flare.json",
      "transform": [
        {
          "type": "stratify",
          "key": "id",
          "parentKey": "parent"
        },
        {
          "type": "partition",
          "field": "size",
          "sort": {"field": "value"},
          "size": [{"signal": "2 * PI"}, {"signal": "width / 2"}],
          "as": ["a0", "r0", "a1", "r1", "depth", "children"]
        }
      ]
    }
  ],

  "scales": [
    {
      "name": "color",
      "type": "ordinal",
      "range": {"scheme": "tableau20"}
    }
  ],

  "marks": [
    {
      "type": "arc",
      "from": {"data": "tree"},
      "encode": {
        "enter": {
          "x": {"signal": "width / 2"},
          "y": {"signal": "height / 2"},
          "fill": {"scale": "color", "field": "depth"},
          "tooltip": {"signal": "datum.name + (datum.size ? ', ' + datum.size + ' bytes' : '')"}
        },
        "update": {
          "startAngle": {"field": "a0"},
          "endAngle": {"field": "a1"},
          "innerRadius": {"field": "r0"},
          "outerRadius": {"field": "r1"},
          "stroke": {"value": "white"},
          "strokeWidth": {"value": 0.5},
          "zindex": {"value": 0}
        },
        "hover": {
          "stroke": {"value": "red"},
          "strokeWidth": {"value": 2},
          "zindex": {"value": 1}
        }
      }
    }
  ]
}