7. The method of claim 6 wherein a subset of the entities and the relationships between the entities are represented by a layer comprising a representation of a subset of the entities, a representation indicating relationships between entities in the subset of the entities, and a control to manipulate the representation of the subset of entities.
7. The method of claim 6 wherein a subset of the entities and the relationships between the entities are represented by a layer comprising a representation of a subset of the entities, a representation indicating relationships between entities in the subset of the entities, and a control to manipulate the representation of the subset of entities. 10. The method of claim 7 , wherein a subset of the entities and relationships between the entities are manipulated by a second layer overlaid over the first layer.