Timelines Example

A custom timeline visualization showing the lifespans of the first five U.S. presidents, including the years each held office. The timeline is additionally annotated with selected historical events.

Vega JSON Specification <>

{
  "$schema": "https://vega.github.io/schema/vega/v3.0.json",
  "width": 500,
  "height": 80,
  "padding": 5,

  "data": [
    {
      "name": "people",
      "values": [
        {
          "label": "Washington",
          "born": -7506057600000,
          "died": -5366196000000,
          "enter": -5701424400000,
          "leave": -5453884800000
        },
        {
          "label": "Adams",
          "born": -7389766800000,
          "died": -4528285200000,
          "enter": -5453884800000,
          "leave": -5327740800000
        },
        {
          "label": "Jefferson",
          "born": -7154586000000,
          "died": -4528285200000,
          "enter": -5327740800000,
          "leave": -5075280000000
        },
        {
          "label": "Madison",
          "born": -6904544400000,
          "died": -4213184400000,
          "enter": -5075280000000,
          "leave": -4822819200000
        },
        {
          "label": "Monroe",
          "born": -6679904400000,
          "died": -4370518800000,
          "enter": -4822819200000,
          "leave": -4570358400000
        }
      ]
    },
    {
      "name": "events",
      "format": {"type":"json", "parse":{"when":"date"}},
      "values": [
        { "name":"Decl. of Independence", "when":"July 4, 1776" },
        { "name":"U.S. Constitution",     "when":"3/4/1789" },
        { "name":"Louisiana Purchase",    "when":"April 30, 1803" },
        { "name":"Monroe Doctrine",       "when":"Dec 2, 1823" }
      ]
    }
  ],

  "scales": [
    {
      "name": "yscale",
      "type": "band",
      "range": [0, {"signal": "height"}],
      "domain": {"data": "people", "field": "label"}
    },
    {
      "name": "xscale",
      "type": "time",
      "range": "width",
      "round": true,
      "domain": {"data": "people", "fields": ["born", "died"]}
    }
  ],

  "axes": [
    {"orient": "bottom", "scale": "xscale"}
  ],

  "marks": [
    {
      "type": "text",
      "from": {"data": "events"},
      "encode": {
        "enter": {
          "x": {"scale": "xscale", "field": "when"},
          "y": {"value": -10},
          "angle": {"value": -25},
          "fill": {"value": "#000"},
          "text": {"field": "name"},
          "fontSize": {"value": 10}
        }
      }
    },
    {
      "type": "rect",
      "from": {"data": "events"},
      "encode": {
        "enter": {
          "x": {"scale": "xscale", "field": "when"},
          "y": {"value": -8},
          "width": {"value": 1},
          "height": {"field": {"group": "height"}, "offset": 8},
          "fill": {"value": "#888"}
        }
      }
    },
    {
      "type": "text",
      "from": {"data": "people"},
      "encode": {
        "enter": {
          "x": {"scale": "xscale", "field": "born"},
          "y": {"scale": "yscale", "field": "label", "offset": -3},
          "fill": {"value": "#000"},
          "text": {"field": "label"},
          "fontSize": {"value": 10}
        }
      }
    },
    {
      "type": "rect",
      "from": {"data": "people"},
      "encode": {
        "enter": {
          "x": {"scale": "xscale", "field": "born"},
          "x2": {"scale": "xscale", "field": "died"},
          "y": {"scale": "yscale", "field": "label"},
          "height": {"value": 2},
          "fill": {"value": "#557"}
        }
      }
    },
    {
      "type": "rect",
      "from": {"data": "people"},
      "encode": {
        "enter": {
          "x": {"scale": "xscale", "field": "enter"},
          "x2": {"scale": "xscale", "field": "leave"},
          "y": {"scale": "yscale", "field": "label", "offset":-1},
          "height": {"value": 4},
          "fill": {"value": "#e44"}
        }
      }
    }
  ]
}