arc.json

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "todo",
  "title": "Arc",
  "width": 400,
  "height": 250,
  "padding": 5,
  "autosize": {"type": "fit", "contains": "padding"},

  "data": [
    {
      "name": "table",
      "url": "./spec/data/ordered-bar.csv",
      "format": {"type": "csv", "parse": "auto"},
      "transform": [
        {
          "type": "pie",
          "field": "Sales",
          "startAngle": -1.57,
          "endAngle": 1.57,
          "sort": false
        }
      ]
    },
    {
      "name": "summary",
      "source": "table",
      "transform": [
        {"type": "aggregate", "groupby": [], "ops": ["sum"], "fields": ["Sales"], "as": ["total"] }
      ]
    }
  ],

  "scales": [
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "table", "field": "Region"},
      "range": ["#96cbff", "#1A8CFF", "#115DAA", "#082A4D"]
    }
  ],

  "marks": [
    {
      "type": "arc",
      "from": {"data": "table"},
      "encode": {
        "update": {
          "fill": {"scale": "color", "field": "Region"},
          "x": {"signal": "width / 2"},
          "y": {"signal": "height"},
          "startAngle": {"field": "startAngle"},
          "endAngle": {"field": "endAngle"},
          "padAngle": {"value": "0.04"},
          "innerRadius": {"signal": "width / 3"},
          "outerRadius": {"signal": "width / 2"},
          "tooltip": {"signal": "datum"}
        }
      }
    },
    {
      "type": "text",
      "from": {"data": "summary"},
      "encode": {
        "enter": {
          "x": {"signal": "width / 2"},
          "y": {"signal": "height - 20"},
          "fill": {"value": "#000"},
          "align": {"value": "center"},
          "baseline": {"value": "middle"},
          "text": {"signal": "format(datum.total, '.0s') + ' Seats'"},
          "fontSize": {"value": 28},
          "fontWeight": {"value": "bold"}
        }
      }
    }
  ]
}