Software Design Center

HOW TO DRAW DATA FLOW DIAGRAMS (cont'd)

Data Flow Diagram Layers
Draw data flow diagrams in several nested layers. A single process node on a high level diagram can be expanded to show a more detailed data flow diagram. Draw the context diagram first, followed by various layers of data flow diagrams.

Context Diagrams
A context diagram is a top level (also known as Level 0) data flow diagram. It only contains one process node (process 0) that generalizes the function of the entire system in relationship to external entities.