Drawing a Context Diagram

Here are a few suggestions to help create a context diagram for the project.

First, make a list of everyone who will interact with the system, what output they will receive, and what input they will provide. You might create a table like the following (which is incomplete).

Creating a New Project in Visio

Start Visio. On the File menu, select New then Choose Drawing Type. You should see a screen similar to the following illustration:
 

 
Choose Software Category and Data Flow Model Diagram as the template.

Creating a Context Diagram in Visio

Once the project is created, Visio gives you a new diagram.
 

 
I changed the magnification to 75%, then I drug a process bubble from the template onto the diagram:
 

 
Notice, in the errors section near the bottom of the screen, that Visio reminds us of process data flow requirements. Clicking inside the process bubble, I changed the process title.
 

 
The next task is to drag an External Agent (Visio calls this an “interface”) and a data flow onto the diagram. Notice that a new error has appeared:
 

 
Give the interface one of the names from the table above. Also, rename the data flow to match one of the data flows you've identified. Add more interfaces and data flows as necessary. To connect a data flow to a process or interface, (1) click on the data flow, (2) drag the appropriate end of the data flow into the symbol to which you wish to connect, (3) when the symbol has a red border (as illustrated below), release the mouse button. The end of the data flow will connect to the symbol and relevant errors should disappear.
 

 
Continue to add interfaces and data flows as necessary. A context diagram normally has only one process and does not contain any data stores.
 

This is a living document that is subject to revision during the course of the class. The most recent versions of course materials can be found at http://www.cbe.wwu.edu/misclasses/mis431W04/. Last revised Tuesday, January 13, 2004; at 7:09:08 AM.