|Status:||Draft (under way)|
|Definition:||An atoll is a coral reef with cays that encircles a lagoon ; it is vestige of an ancient volcanic island.|
Anis a coral reef including a coral rim with cays (waterless sandy islets) that encircles a lagoon ; it is vestige of an ancient volcanic island.
Node or area?
You can tag this as a single node, an area delimited by the coral reef (natural=reef) or a relation (Relation:site linking the different place=islets or Relation:multipolygon with the coral reef as outer boundary and the lagoon as inner boundary).