{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Support contacts by channel (streamgraph)",
  "mark": {"type": "area", "interpolate": "monotone", "opacity": 0.9},
  "data": {
    "values": [
      {"week": 1, "channel": "email", "contacts": 120},
      {"week": 2, "channel": "email", "contacts": 150},
      {"week": 3, "channel": "email", "contacts": 190},
      {"week": 4, "channel": "email", "contacts": 165},
      {"week": 5, "channel": "email", "contacts": 130},
      {"week": 6, "channel": "email", "contacts": 110},
      {"week": 1, "channel": "chat", "contacts": 40},
      {"week": 2, "channel": "chat", "contacts": 95},
      {"week": 3, "channel": "chat", "contacts": 210},
      {"week": 4, "channel": "chat", "contacts": 330},
      {"week": 5, "channel": "chat", "contacts": 300},
      {"week": 6, "channel": "chat", "contacts": 240},
      {"week": 1, "channel": "phone", "contacts": 220},
      {"week": 2, "channel": "phone", "contacts": 180},
      {"week": 3, "channel": "phone", "contacts": 140},
      {"week": 4, "channel": "phone", "contacts": 105},
      {"week": 5, "channel": "phone", "contacts": 85},
      {"week": 6, "channel": "phone", "contacts": 70},
      {"week": 1, "channel": "forum", "contacts": 30},
      {"week": 2, "channel": "forum", "contacts": 45},
      {"week": 3, "channel": "forum", "contacts": 60},
      {"week": 4, "channel": "forum", "contacts": 110},
      {"week": 5, "channel": "forum", "contacts": 175},
      {"week": 6, "channel": "forum", "contacts": 260}
    ]
  },
  "encoding": {
    "x": {"field": "week", "type": "quantitative", "axis": {"title": "week"}},
    "y": {
      "aggregate": "sum",
      "field": "contacts",
      "type": "quantitative",
      "stack": "center",
      "axis": {"title": "contacts (centred)"}
    },
    "color": {"field": "channel", "type": "nominal"}
  }
}