I have the big use-case diagram:
May I pack some use-cases in packages and then show diagram by the following way:
I think you're missing the point of use case diagrams. They aren't to say, here's an actor, here's a use case. Your diagrams should be taking me through the story of a use case. That story should be more than just one oval. Whether you should be bundling multiple use cases together in one diagram has more to do with how complex the use cases are and if they fit on one page.
If you're just looking for a way to abstract similar use cases together because the rest of their story is identical then sure. Use whatever grouping picture you like. Just be consistent.
If you wish to show a multitude of something without giving each one a different label the stack has always been my choice. It's easy to do on the whiteboard as well.
With this you can start to ask, is the package box still needed? Could each oval simply be labeled "basic use case" and "additional use case"? If the oval is known to be a use case can you just use "basic" and "additional"?
In most of my projects we used a distinction between Diagram
and Model
in the way that a diagram always shows a view of the Use Case Model
.
In other words: a diagram is purposed towards the readability and per se not complete in the sense that all model elements are visible.
Therefore:
yes, as CandiedOrange suggested, you can show the actor (or actors) of each Use Case
in a separate diagram (but it would be overkill of course).
I would recommend that you show all the Use Cases
you want to mention/talk about in one diagram - to show
User Story
, or Actor
or Role
. Create several diagrams and name each of them according to the purpose of what the diagram is supposed to explain.
Use (or abuse) the package
element in any way you like as long as you feel that your audience gets a benefit out of it. (I'm fine with it, just like Doc Brown)
Depending on the UML tool you are using, you might want to use additional graphical elements to mark or group Use Cases.
And yes, as kind of your signature it is best practice in my experience to stay consistent in the additions you make. You don't have to stick to one thing you chose forever (IMHO) but your audience will have a hard time adjusting if you frequently introduce new ways of expressing the logic of the software or the processes the software supports or implements. It is tempting to do this with a Use Case Diagram
... I know.
Referring more to the title of your question than its phrasing:
Why not print it in Wallpaper size?
I think Use Case Diagrams
are made for huge displays and there is no better way to showing off the BIG PICTURE.