Encoding Duration Channel

The duration channel sets the length of each tone (only works for discrete tones) that encodes a data value in a different scale than that of the time channel. An example case is mapping a year field to the time channel and a price field to the duration channel. The default unit is seconds. The duration channel has a relatively simple usage pattern.

duration usage pattern

JSON

{
  ...
  "encoding" : {
    "duration": {
      "field": "Body Mass (g)",
      "type": "quantitative",
      "scale": {
        "doamin": [0, 7000], // optional
        "range": [0, 1]
      }
    }
  }
  ...
}

JavaScript

let stream = new Erie.Stream();
...
stream.encoding.time.field("Body Mass (g)", "quantitative");
stream.encoding.time.scale("domain", [0, 7000]); // optinal
stream.encoding.time.scale("range", [0, 1]); // unit: seconds
...
© Hyeok Kim