{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "A trellis bar chart showing the US population distribution of age groups and gender in 2000.",
  "background": "white",
  "padding": 5,
  "data": [
    {
      "name": "source_0",
      "url": "data/population.json",
      "format": {"type": "json"},
      "transform": [
        {"type": "filter", "expr": "datum.year == 2000"},
        {
          "type": "formula",
          "expr": "datum.sex == 2 ? 'Female' : 'Male'",
          "as": "gender"
        }
      ]
    },
    {
      "name": "column_domain",
      "source": "source_0",
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["gender"],
          "fields": ["age"],
          "ops": ["distinct"],
          "as": ["distinct_age"]
        }
      ]
    },
    {
      "name": "data_1",
      "source": "source_0",
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["age", "gender"],
          "ops": ["sum"],
          "fields": ["people"],
          "as": ["sum_people"]
        }
      ]
    },
    {
      "name": "data_2",
      "source": "data_1",
      "transform": [
        {
          "type": "filter",
          "expr": "isValid(datum[\"sum_people\"]) && isFinite(+datum[\"sum_people\"])"
        }
      ]
    }
  ],
  "signals": [
    {"name": "child_x_step", "value": 17},
    {"name": "child_height", "value": 200}
  ],
  "layout": {
    "padding": 20,
    "offset": {"columnTitle": 10},
    "columns": {"signal": "length(data('column_domain'))"},
    "bounds": "full",
    "align": "none"
  },
  "marks": [
    {
      "name": "column-title",
      "type": "group",
      "role": "column-title",
      "title": {"text": "gender", "style": "guide-title", "offset": 10}
    },
    {
      "name": "row_header",
      "type": "group",
      "role": "row-header",
      "encode": {"update": {"height": {"signal": "child_height"}}},
      "axes": [
        {
          "scale": "y",
          "orient": "left",
          "grid": false,
          "title": "population",
          "labelOverlap": true,
          "tickCount": {"signal": "ceil(child_height/40)"},
          "zindex": 0
        }
      ]
    },
    {
      "name": "column_header",
      "type": "group",
      "role": "column-header",
      "from": {"data": "column_domain"},
      "sort": {"field": "datum[\"gender\"]", "order": "ascending"},
      "title": {
        "text": {
          "signal": "isValid(parent[\"gender\"]) ? parent[\"gender\"] : \"\"+parent[\"gender\"]"
        },
        "style": "guide-label",
        "frame": "group",
        "offset": 10
      },
      "encode": {
        "update": {
          "width": {
            "signal": "bandspace(datum[\"distinct_age\"], 1, 0.5) * child_x_step"
          }
        }
      }
    },
    {
      "name": "cell",
      "type": "group",
      "style": "cell",
      "from": {
        "facet": {
          "name": "facet",
          "data": "source_0",
          "groupby": ["gender"],
          "aggregate": {
            "fields": ["age"],
            "ops": ["distinct"],
            "as": ["distinct_age"]
          }
        }
      },
      "sort": {"field": ["datum[\"gender\"]"], "order": ["ascending"]},
      "data": [
        {
          "source": "facet",
          "name": "data_0",
          "transform": [
            {
              "type": "aggregate",
              "groupby": ["age", "gender"],
              "ops": ["sum"],
              "fields": ["people"],
              "as": ["sum_people"]
            }
          ]
        },
        {
          "name": "data_1",
          "source": "data_0",
          "transform": [
            {
              "type": "filter",
              "expr": "isValid(datum[\"sum_people\"]) && isFinite(+datum[\"sum_people\"])"
            }
          ]
        }
      ],
      "encode": {
        "update": {
          "width": {
            "signal": "bandspace(datum[\"distinct_age\"], 1, 0.5) * child_x_step"
          },
          "height": {"signal": "child_height"}
        }
      },
      "marks": [
        {
          "name": "child_layer_0_pathgroup",
          "type": "group",
          "from": {
            "facet": {
              "name": "faceted_path_child_layer_0_main",
              "data": "data_0",
              "groupby": ["gender"]
            }
          },
          "encode": {
            "update": {
              "width": {"field": {"group": "width"}},
              "height": {"field": {"group": "height"}}
            }
          },
          "marks": [
            {
              "name": "child_layer_0_marks",
              "type": "line",
              "style": ["line"],
              "sort": {"field": "datum[\"age\"]"},
              "from": {"data": "faceted_path_child_layer_0_main"},
              "encode": {
                "update": {
                  "stroke": {"scale": "color", "field": "gender"},
                  "description": {
                    "signal": "\"age: \" + (isValid(datum[\"age\"]) ? datum[\"age\"] : \"\"+datum[\"age\"]) + \"; population: \" + (format(datum[\"sum_people\"], \"\")) + \"; gender: \" + (isValid(datum[\"gender\"]) ? datum[\"gender\"] : \"\"+datum[\"gender\"])"
                  },
                  "x": {"scale": "child_x", "field": "age"},
                  "y": {"scale": "y", "field": "sum_people"},
                  "defined": {
                    "signal": "isValid(datum[\"sum_people\"]) && isFinite(+datum[\"sum_people\"])"
                  }
                }
              }
            }
          ]
        },
        {
          "name": "child_layer_1_marks",
          "type": "symbol",
          "style": ["point"],
          "from": {"data": "data_1"},
          "encode": {
            "update": {
              "fill": {"value": "transparent"},
              "stroke": {"scale": "color", "field": "gender"},
              "ariaRoleDescription": {"value": "point"},
              "description": {
                "signal": "\"age: \" + (isValid(datum[\"age\"]) ? datum[\"age\"] : \"\"+datum[\"age\"]) + \"; population: \" + (format(datum[\"sum_people\"], \"\")) + \"; gender: \" + (isValid(datum[\"gender\"]) ? datum[\"gender\"] : \"\"+datum[\"gender\"])"
              },
              "x": {"scale": "child_x", "field": "age"},
              "y": {"scale": "y", "field": "sum_people"}
            }
          }
        }
      ],
      "scales": [
        {
          "name": "child_x",
          "type": "point",
          "domain": {
            "fields": [
              {"data": "data_0", "field": "age"},
              {"data": "data_1", "field": "age"}
            ],
            "sort": true
          },
          "range": {"step": {"signal": "child_x_step"}},
          "padding": 0.5
        }
      ],
      "axes": [
        {
          "scale": "y",
          "orient": "left",
          "gridScale": "child_x",
          "grid": true,
          "tickCount": {"signal": "ceil(child_height/40)"},
          "domain": false,
          "labels": false,
          "aria": false,
          "maxExtent": 0,
          "minExtent": 0,
          "ticks": false,
          "zindex": 0
        },
        {
          "scale": "child_x",
          "orient": "bottom",
          "grid": false,
          "title": "age",
          "labelAlign": "right",
          "labelAngle": 270,
          "labelBaseline": "middle",
          "zindex": 0
        }
      ]
    }
  ],
  "scales": [
    {
      "name": "y",
      "type": "linear",
      "domain": {
        "fields": [
          {"data": "data_1", "field": "sum_people"},
          {"data": "data_2", "field": "sum_people"}
        ]
      },
      "range": [{"signal": "child_height"}, 0],
      "nice": true,
      "zero": true
    },
    {
      "name": "color",
      "type": "ordinal",
      "domain": {
        "fields": [
          {"data": "data_1", "field": "gender"},
          {"data": "data_2", "field": "gender"}
        ],
        "sort": true
      },
      "range": ["#675193", "#ca8861"]
    }
  ],
  "legends": [
    {
      "stroke": "color",
      "symbolType": "circle",
      "title": "gender",
      "encode": {"symbols": {"update": {"fill": {"value": "transparent"}}}}
    }
  ],
  "config": {"style": {"cell": {"fill": "yellow"}}}
}