How to represent a use case diagram with many use cases

Question

I'm using PowerDesigner and I have a use case diagram with one actor and 28 use cases, I'm looking for the best way to represent it in one paper.

I tried the vertical center alignment of use cases, but it takes a lot of space.

Can I split them in two or three packages or something like that ?

Answer 1

I have a use case with one actor and 28 use cases

What do you mean by this? A use case "with" 28 use cases? In UML it is not valid for a use case to "contain" other use cases. If you did it like this, simply convert the containing UC into a Package with the same name.

Are these 28 UC maybe included in the first one ("include" relationship)? If so, this already seems to be strange. We should know more in order to eventually fix this.

There are several ways you can visually simplify similar modelling situations. In general, you should not have more then 6-8 elements (UCs) in one diagram, simplicity reasons.

• Make several diagrams and show only related use cases on each one, with corresponding (in this case always the same) actor
• Are all use cases on the same level of abstraction? If not, consider restructuring them in terms of converting high-level ones into packages which would in turn contain corresponding low-level use cases
• Are use cases maybe too atomic (too low-level)? If so, group several related ones in a higher-level use case. This would reduce the total of UCs
• Do you have some relationships between them?

If you post your current diagram, we could probably help you further.