Type Alias: SpatialAnchor

type SpatialAnchor = 
  | {
  altM?: number;
  kind: "geo";
  lat: number;
  lonEast: number;
}
  | {
  kind: "named";
  placeId: string;
}
  | {
  kind: "region";
  lat: number;
  lonEast: number;
  radiusKm: number;
}
  | {
  anchorId: string;
  kind: "relative";
  relation: "near" | "at";
}
  | {
  kind: "fictional";
  value: string;
}
  | {
  kind: "none";
  reason: "heliocentric" | "atemporal" | "intentionally_unset";
};

How a chart's place is known -- the spatial twin of TemporalAnchor.