Histogram Sort Criteria

Sorted_Relative_Histogram.vl.json

{
  "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
  "data": { "values": [
    {"Cylinders": 3, "Origin": "Europe"},
    {"Cylinders": 3, "Origin": "Europe"},
    {"Cylinders": 3, "Origin": "Europe"},
    {"Cylinders": 4, "Origin": "Europe"},
    {"Cylinders": 4, "Origin": "Europe"},
    {"Cylinders": 5, "Origin": "Europe"},
    {"Cylinders": 6, "Origin": "Europe"},
    {"Cylinders": 6, "Origin": "Europe"},
    {"Cylinders": 3, "Origin": "USA"},
    {"Cylinders": 3, "Origin": "USA"},
    {"Cylinders": 3, "Origin": "USA"},
    {"Cylinders": 3, "Origin": "USA"},
    {"Cylinders": 4, "Origin": "USA"},
    {"Cylinders": 5, "Origin": "USA"},
    {"Cylinders": 5, "Origin": "USA"},
    {"Cylinders": 6, "Origin": "USA"},
    {"Cylinders": 6, "Origin": "USA"},
    {"Cylinders": 6, "Origin": "USA"},
    {"Cylinders": 3, "Origin": "Japan"},
    {"Cylinders": 3, "Origin": "Japan"},
    {"Cylinders": 4, "Origin": "Japan"},
    {"Cylinders": 5, "Origin": "Japan"},
    {"Cylinders": 4, "Origin": "Japan"}
  ]},
  "transform": [{
      "aggregate": [{"op": "count", "as": "Count"}],
      "groupby": ["Cylinders", "Origin"]
    }, {
      "impute": "Count",
      "value": 0,
      "key": "Origin",
      "groupby": ["Cylinders"]
    }, {
      "joinaggregate": [{"op": "sum", "field": "Count", "as": "OriginCount"}],
      "groupby": ["Origin"]
    },{
      "joinaggregate": [{"op": "sum", "field": "Count", "as": "CategoryItemSum"}],
      "groupby": ["Cylinders"]
    }, {
      "calculate": "datum.Count/datum.OriginCount", "as": "PercentOfOrigin"
    }, {
      "joinaggregate": [{"op": "sum", "field": "PercentOfOrigin", "as": "CategoryPercentSum"}],
      "groupby": ["Cylinders"]
    }, {
      "joinaggregate": [{"op": "max", "field": "PercentOfOrigin", "as": "maxPercent"}],
      "groupby": ["Cylinders"]
    }, {
      "joinaggregate": [{"op": "average", "field": "PercentOfOrigin", "as": "avgPercent"}],
      "groupby": ["Cylinders"]
    }, {
      "calculate": "pow(datum.avgPercent-datum.PercentOfOrigin,2)", "as": "squaredError"
    }, {
      "joinaggregate": [{"op": "average", "field": "squaredError", "as": "meanSquaredError"}],
      "groupby": ["Cylinders"]
    }
  ],
  "mark": {"type": "bar", "tooltip": true},
  "encoding": {
    "y": {
      "field": "Origin", 
      "type": "nominal",
      "axis": {
        "title": null,
        "labels": false,
        "ticks": false
      }
    },
    "x": {
      "field": "PercentOfOrigin",
      "type": "quantitative",
      "axis": {
        "title": "Relative Frequency (per Origin)",
        "format": ".1~%"
        }
    },
    "row": {
      "field": "Cylinders",
      "type": "nominal",
      "spacing": -2,
      "sort": {
        "field": "meanSquaredError",
        "order": "descending"
      }
    },
    "color": {
      "field": "Origin",
      "type": "nominal"
    }
  }
}