单线的 Vega 折线图答案

【问题标题】：Vega line chart with a single line单线的 Vega 折线图
【发布时间】：2017-08-21 22:23:14
【问题描述】：

如何在Vega 中创建一个只有一条线的折线图？ vega 提供了一个示例：https://vega.github.io/vega/examples/line-chart/，它有多行。不提供单行示例。

如何将此示例更改为只有一行？是在下面规范的marks 部分吗？

{
  "$schema": "https://vega.github.io/schema/vega/v3.0.json",
  "width": 500,
  "height": 200,
  "padding": 5,

  "signals": [
    {
      "name": "interpolate",
      "value": "linear",
      "bind": {
        "input": "select",
        "options": [
          "basis",
          "cardinal",
          "catmull-rom",
          "linear",
          "monotone",
          "natural",
          "step",
          "step-after",
          "step-before"
        ]
      }
    }
  ],

  "data": [
    {
      "name": "table",
      "values": [
        {"x": 0, "y": 28, "c":0}, {"x": 0, "y": 20, "c":1},
        {"x": 1, "y": 43, "c":0}, {"x": 1, "y": 35, "c":1},
        {"x": 2, "y": 81, "c":0}, {"x": 2, "y": 10, "c":1},
        {"x": 3, "y": 19, "c":0}, {"x": 3, "y": 15, "c":1},
        {"x": 4, "y": 52, "c":0}, {"x": 4, "y": 48, "c":1},
        {"x": 5, "y": 24, "c":0}, {"x": 5, "y": 28, "c":1},
        {"x": 6, "y": 87, "c":0}, {"x": 6, "y": 66, "c":1},
        {"x": 7, "y": 17, "c":0}, {"x": 7, "y": 27, "c":1},
        {"x": 8, "y": 68, "c":0}, {"x": 8, "y": 16, "c":1},
        {"x": 9, "y": 49, "c":0}, {"x": 9, "y": 25, "c":1}
      ]
    }
  ],

  "scales": [
    {
      "name": "x",
      "type": "point",
      "range": "width",
      "domain": {"data": "table", "field": "x"}
    },
    {
      "name": "y",
      "type": "linear",
      "range": "height",
      "nice": true,
      "zero": true,
      "domain": {"data": "table", "field": "y"}
    },
    {
      "name": "color",
      "type": "ordinal",
      "range": "category",
      "domain": {"data": "table", "field": "c"}
    }
  ],

  "axes": [
    {"orient": "bottom", "scale": "x"},
    {"orient": "left", "scale": "y"}
  ],

  "marks": [
    {
      "type": "group",
      "from": {
        "facet": {
          "name": "series",
          "data": "table",
          "groupby": "c"
        }
      },
      "marks": [
        {
          "type": "line",
          "from": {"data": "series"},
          "encode": {
            "enter": {
              "x": {"scale": "x", "field": "x"},
              "y": {"scale": "y", "field": "y"},
              "stroke": {"scale": "color", "field": "c"},
              "strokeWidth": {"value": 2}
            },
            "update": {
              "interpolate": {"signal": "interpolate"},
              "fillOpacity": {"value": 1}
            },
            "hover": {
              "fillOpacity": {"value": 0.5}
            }
          }
        }
      ]
    }
  ]
}

【问题讨论】：

一旦问题得到答案，您就无法真正重写问题，以至于答案不再有效。如果您有更多问题，请单独提问。
@RobertLongson 是的，我并不是真的打算改变这个问题，只是编辑了太多。我关于 y 轴的问题在这里：stackoverflow.com/q/45812279/325727

标签： svg charts vega

【解决方案1】：

只需删除一些数据。 “c”:0 数据构成一行，“c”:1 数据构成另一行。我删除了下面的 "c": 1 数据。

 "data": [
    {
      "name": "table",
      "values": [
        {"x": 0, "y": 28, "c":0},
        {"x": 1, "y": 43, "c":0},
        {"x": 2, "y": 81, "c":0},
        {"x": 3, "y": 19, "c":0},
        {"x": 4, "y": 52, "c":0},
        {"x": 5, "y": 24, "c":0},
        {"x": 6, "y": 87, "c":0},
        {"x": 7, "y": 17, "c":0},
        {"x": 8, "y": 68, "c":0},
        {"x": 9, "y": 49, "c":0}
      ]
    }
  ],

【讨论】：