{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "US states (admin-1)",
  "data": {"feature_collection": {"tier": "admin1-50m"}},
  "transform": [
    {"filter": "parent == \"USA\""}
  ],
  "mark": "geoshape",
  "projection": {"type": "albers_usa", "tier": "admin1-50m"},
  "encoding": {
    "feature": {"field": "id", "type": "nominal"}
  }
}