How to draw diagonal rule in Vega Lite? - Stack Overflow

This code should produce diagonal line from [x=0, y=0] to [x2=1, y2=1], but produces empty chart playground:

{
  "encoding": {
    "x": {
      "value": 0,
      "type": "quantitative"
    },
    "x2": {
      "value": 1,
      "type": "quantitative"
    },
    "y": {
      "value": 0,
      "type": "quantitative"
    },
    "y2": {
      "value": 1,
      "type": "quantitative"
    }
  },
  "mark": {
    "type": "rule"
  }
}

I want to set data points explicitly with the value, not reference it from the data, as the actual plot is more complicated and rule needs to be added separately from the data.

This code should produce diagonal line from [x=0, y=0] to [x2=1, y2=1], but produces empty chart playground:

{
  "encoding": {
    "x": {
      "value": 0,
      "type": "quantitative"
    },
    "x2": {
      "value": 1,
      "type": "quantitative"
    },
    "y": {
      "value": 0,
      "type": "quantitative"
    },
    "y2": {
      "value": 1,
      "type": "quantitative"
    }
  },
  "mark": {
    "type": "rule"
  }
}

I want to set data points explicitly with the value, not reference it from the data, as the actual plot is more complicated and rule needs to be added separately from the data.

• vega-lite
• vega

Share Improve this question Follow asked Jan 7 at 3:29 Alex CraftAlex Craft 15.5k1414 gold badges9090 silver badges156156 bronze badges

Add a comment  | 

1 Answer 1

Sorted by: Reset to default 3

Two changes to make:

1. You need data, even if empty.
2. The property for the literal values here is "datum", not "value". I don't fully understand the difference between the two, but I believe datum is used when there is an existing scale/domain in play (the x- and y-axes), whereas value is used in the absence of a preexisting scale/domain (e.g. color and shape of points in a plot that doesn't assign them to a channel).

{
  "encoding": {
    "x": {"datum": 0, "type": "quantitative"},
    "x2": {"datum": 1, "type": "quantitative"},
    "y": {"datum": 0, "type": "quantitative"},
    "y2": {"datum": 1, "type": "quantitative"}
  },
  "mark": {"type": "rule"},
  "data": {"values": [{}]}
}