This Interaction Overview Diagram is an activity diagram variant. The distinction is that the nodes in interaction overview diagrams represent the occurrences of interactions in a system or piece of software. Interaction overview diagrams can show the flow of activity between charts using a similar notation to activity diagrams (initial, final, merge, fork, decision), interaction occurrences, and interactive elements. While interaction overview diagrams share many symbols and notations as activity diagrams, they add two new elements: interaction elements and interaction occurrences.
