Visualizing System Processes: Examples of Data Flow Diagram Level 0, 1, and 2 for Effective Analysis. Heart Diagram Guide › Analysis › Diagram › Effective › Examples › Level › Processes › System › Visualizing Admin June 29, 2023 Learn about Data Flow Diagrams (DFD) at different levels- Level 0, 1, and 2 with examples. Understand how data moves through a system.