rule Graphical2Textual
transform g: coronagraphical!Country
to t: coronatextual!Country

{
t.name = g.name;
t.population = g.population;
t.zone = g.zone;
} 

The value of type 'class org.eclipse.emf.ecore.impl.EEnumLiteralImpl' must be of type 'org.eclipse.emf.ecore.impl.EEnumImpl@27cd4e69 (name: zonelabelcolour) (instanceClassName: null) (serializable: true)'

rule Graphical2Textual
transform g: coronagraphical!Country
to t: coronatextual!Country {
  t.name = g.name;
  t.population = g.population;
  t.zone = g.zone.toContextualZone();
} 

operation Any toContextualZone() {
  if (self == coronagraphical!zonelabel#low) return contextual!zonelabel#low;
  // etc.
}

operation coronagraphical!Country toContextualZone() {
  if (self.zone == coronagraphical!zonelabel#low) return contextual!zonelabel#low;
  // etc.
}