GaneSarson

Gane-Sarson notation is a data flow diagram (DFD) notation used in structured analysis and design to model how data moves through a system. It was developed in the 1970s by Gane and Sarson as part of early data-centric methods for information systems analysis. The notation is used to produce Data Flow Diagrams that illustrate the sources and destinations of data (external entities), the processes that transform data, the data stores that hold data, and the data flows that connect these elements. The approach emphasizes hierarchical decomposition: analysts create high-level diagrams and progressively decompose processes into subprocesses across levels, while maintaining balance of inputs and outputs between levels.

Symbols are defined for the four data-objects: external entities, processes, data stores, and data flows; the choice of shapes and conventions varies by edition but the relationships are consistent. Gane-Sarson diagrams are often contrasted with the Yourdon notation, which is a later, alternative DFD convention.

In practice, Gane-Sarson is used for systems analysis and requirements gathering, especially in business information systems. It supports clear visualization of data movement, interfaces, and data persistence, aiding communication among analysts, developers, and stakeholders. Limitations include potential diagram complexity for large systems and the need for careful management of levels to ensure consistency and avoid misinterpretation.

Legacy: Though some organizations have migrated to other notations or modeling languages, Gane-Sarson remains a foundational reference for DFD-based analysis and is covered in many textbooks and training materials.