{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "World choropleth (GDP tier)",
  "data": {
    "name": "metrics",
    "values": [
      {"id": "USA", "tier": "high"},
      {"id": "CAN", "tier": "high"},
      {"id": "GBR", "tier": "high"},
      {"id": "FRA", "tier": "high"},
      {"id": "DEU", "tier": "high"},
      {"id": "JPN", "tier": "high"},
      {"id": "AUS", "tier": "high"},
      {"id": "ITA", "tier": "mid"},
      {"id": "ESP", "tier": "mid"},
      {"id": "BRA", "tier": "mid"},
      {"id": "MEX", "tier": "mid"},
      {"id": "RUS", "tier": "mid"},
      {"id": "CHN", "tier": "mid"},
      {"id": "ZAF", "tier": "low"},
      {"id": "IND", "tier": "low"},
      {"id": "EGY", "tier": "low"}
    ]
  },
  "mark": "geoshape",
  "projection": {"type": "naturalearth"},
  "encoding": {
    "feature": {"field": "id",   "type": "nominal"},
    "color":   {"field": "tier", "type": "nominal"}
  }
}