Activity on Arrow (A-O-A) or (A-O-L):-
- It is composed of arrows and nodes. The arrows represent the activities and nodes represent the events.
- Each activity carries a brief description usually printed on the logical diagram, the activity name or symbol and the time duration.
- At present, this method seems to be the most popular method and it was the first method to be introduced, developed and computerized
Activity on node (A-O-N) or Precedence diagrams:-
- In A-O-N networks, the nodes represent the activities and the arrows, their interdependencies or precedence relationships.
- Nodes are usually represented by squares or rectangles, but circles and other convenient geometrical shapes may also be used.
- Activity number and description are written within the boxes representing the nodes.
- Length and direction of the arrows have no significance as they indicate only the dependency of one activity on another.