Data Flow diagrams are widely used in software engineering,
information systems, and data base design.
They represent processes and flows of data between processes.
They have three types of symbols.
Namely, interfaces, repositories, and processes.
Interfaces represent the "boundaries" of the system.
Repositories represent information stored in the system.
Processes represent agents (for example
SW modules) that elaborate information. Interfaces, processes, and repositories
are usually represented as squares, smoothed squares, and right-open rectangles,
Connections between symbols are usually "directed". The arrow along a
connection illustrates the direction of the flow of information.
Speaking in terms of graph properties, Data Flow diagrams are directed graphs.
We suggest to represent Data Flow diagrams with orthogonal drawings, i.e.,
drawings in which the connections between symbols consist of horizontal
and vertical segments only.
The following figure shows an example of Data Flow diagram constructed with
GAPI tutorial on orthogonal drawings
BLAG tutorial on orthogonal drawings
provide a comprehensive guide on how to use GDT to construct these widely
Last update : July 31, 2002
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