使用 vconcat 和 hconcat 在 vega 中创建绘图矩阵时如何对齐轴？

Question

考虑绘图矩阵（例如 3 x 3 散点图网格），其中所有维度共享轴，但不同轴的比例不同（例如，考虑日期、对数数量、线性）。

为此，您可以通过图表规范的 vconcat 和 hconcat 创建一个矩阵。

从文档看来，您应该使用 minExtent 和 maxExtent 来对齐轴，但是我不清楚 在哪里 应用此配置？它需要处于最低图表规范级别，因为轴范围都不同，具体取决于所考虑矩阵的角色和列。

查看图片以获取未对齐示例

Answer 1

根据docs，您需要在axis配置中提供minExtent和maxExtent。

以下是示例配置或参考editor：

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "description": "Two horizonally concatenated charts that show a histogram of precipitation in Seattle and the relationship between min and max temperature.",
  "data": {"url": "data/weather.csv"},
  "transform": [{"filter": "datum.location === 'Seattle'"}],
  "columns": 3,
  "config": {"axisY": {"minExtent": 50, "maxExtent": 100}},
  "concat": [
    {
      "mark": "bar",
      "encoding": {
        "x": {"timeUnit": "month", "field": "date", "type": "ordinal"},
        "y": {
          "aggregate": "mean",
          "field": "precipitation",
          "axis": {"format": ".4f"}
        }
      }
    },
    {
      "mark": "bar",
      "encoding": {
        "x": {"timeUnit": "month", "field": "date", "type": "ordinal"},
        "y": {"aggregate": "median", "field": "precipitation"}
      }
    },
    {
      "mark": "point",
      "encoding": {
        "x": {"field": "temp_min", "bin": true},
        "y": {"field": "temp_max", "bin": true},
        "size": {"aggregate": "count"}
      }
    },
    {
      "mark": "point",
      "encoding": {
        "x": {"field": "temp_min", "bin": true},
        "y": {"field": "temp_max", "bin": true},
        "size": {"aggregate": "count"}
      }
    },
    {
      "mark": "point",
      "encoding": {
        "x": {"field": "temp_min", "bin": true},
        "y": {"field": "temp_max", "bin": true},
        "size": {"aggregate": "count"}
      }
    },
    {
      "mark": "point",
      "encoding": {
        "x": {"field": "temp_min", "bin": true},
        "y": {"field": "temp_max", "bin": true},
        "size": {"aggregate": "count"}
      }
    }
  ]
}