{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "background": "white",
  "padding": 5,
  "data": [
    {
      "name": "source_0",
      "url": "data/barley.json",
      "format": {"type": "json"},
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["site", "year"],
          "ops": ["sum"],
          "fields": ["yield"],
          "as": ["sum_yield"]
        },
        {
          "type": "stack",
          "groupby": ["year"],
          "field": "sum_yield",
          "sort": {"field": ["site"], "order": ["ascending"]},
          "as": ["sum_yield_start", "sum_yield_end"],
          "offset": "zero"
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"sum_yield\"]) && isFinite(+datum[\"sum_yield\"])"
        }
      ]
    },
    {
      "name": "column_domain",
      "source": "source_0",
      "transform": [{"type": "aggregate", "groupby": ["year"]}]
    }
  ],
  "signals": [
    {"name": "child_width", "value": 200},
    {"name": "child_height", "value": 200}
  ],
  "layout": {
    "padding": 20,
    "offset": {"columnTitle": 10},
    "columns": {"signal": "length(data('column_domain'))"},
    "bounds": "full",
    "align": "all"
  },
  "marks": [
    {
      "name": "column-title",
      "type": "group",
      "role": "column-title",
      "title": {"text": "year", "style": "guide-title", "offset": 10}
    },
    {
      "name": "column_header",
      "type": "group",
      "role": "column-header",
      "from": {"data": "column_domain"},
      "sort": {"field": "datum[\"year\"]", "order": "ascending"},
      "title": {
        "text": {
          "signal": "isValid(parent[\"year\"]) ? parent[\"year\"] : \"\"+parent[\"year\"]"
        },
        "style": "guide-label",
        "frame": "group",
        "offset": 10
      },
      "encode": {"update": {"width": {"signal": "child_width"}}}
    },
    {
      "name": "cell",
      "type": "group",
      "from": {
        "facet": {"name": "facet", "data": "source_0", "groupby": ["year"]}
      },
      "sort": {"field": ["datum[\"year\"]"], "order": ["ascending"]},
      "encode": {
        "update": {
          "width": {"signal": "child_width"},
          "height": {"signal": "child_height"}
        }
      },
      "marks": [
        {
          "name": "child_marks",
          "type": "arc",
          "style": ["arc"],
          "from": {"data": "facet"},
          "encode": {
            "update": {
              "fill": {"scale": "color", "field": "site"},
              "description": {
                "signal": "\"Sum of yield: \" + (format(datum[\"sum_yield\"], \"\")) + \"; site: \" + (isValid(datum[\"site\"]) ? datum[\"site\"] : \"\"+datum[\"site\"])"
              },
              "x": {"signal": "child_width", "mult": 0.5},
              "y": {"signal": "child_height", "mult": 0.5},
              "outerRadius": {"signal": "min(child_width,child_height)/2"},
              "innerRadius": {"value": 0},
              "startAngle": {"scale": "child_theta", "field": "sum_yield_end"},
              "endAngle": {"scale": "child_theta", "field": "sum_yield_start"}
            }
          }
        }
      ],
      "scales": [
        {
          "name": "child_theta",
          "type": "linear",
          "domain": {
            "data": "facet",
            "fields": ["sum_yield_start", "sum_yield_end"]
          },
          "range": [0, 6.283185307179586],
          "zero": true
        }
      ]
    }
  ],
  "scales": [
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "source_0", "field": "site", "sort": true},
      "range": "category"
    }
  ],
  "legends": [{"fill": "color", "symbolType": "circle", "title": "site"}]
}