What UML diagram should I use for simple application features..?

I'm really confused about this, tried to read a lot about diagrams but I just can't understand what is most suitable for this case.

I need just TO SHOW that I have 10 modules, which have 10 features. One of that feature can call other module feature..

something like this. very simple. it's better just to be some kind of blocks with depedencies[as features] and how each module block will interact with another block

purpose is to show what open source system doesn't have, and what this system WILL have after modification. And ofcourse with colors, it's easy to display all modifications.. than it's easier to start planning a project and count how much hours will be spen开发者_如何转开发t on things you need to make..

Indeed as other stated, UML does not support directly what you need. As far as I understand, you want capture the structure (modules), behaviour (features) and interactions (dependencies), although in a basic form, still you aim to capture too much at the same time.

So let us review your possibilities with UML, I hope this will help you decide:

1. Package diagram can show structure and dependencies as packages and imports

2. Component diagram can capture structure and dependencies as components with connectors

3. Composite Structure diagram allow to depict complex structure and interactions through composites, ports, connectors and collaborations

4. Use case diagram contains actors interacting with the system to perform use cases, which can be combined with the package diagram to simply decompose system in different modules, which provide different features - use cases and for depicting interactions you can connect actors with use cases.

So, as you guess my choice will be the use case diagram with package diagram. Those are goth quite simple, containing small amount of noise, which might be essential for your simple case. This combination allows for most of what you need, however, to show that modules interact in certain way, you would need to have a module both as a package and as an actor, which is not a good practice. But from what you say I guess you want to advertise change of existing system, which will look nice in those diagrams and will be easy to explain to customers who know nothing about UML. You might consider removing interactions between modules and show only features provided to users (depicted as actors).

The very reason you are confused is that the creators of UML just made a catalog of their diagrams (a dozen types) and never really tells you when to use one or the other.

If you're talking about features, it means use case diagrams. You can see some examples here: http://askuml.com/blog/login-page-use-case-diagram/ or http://askuml.com/blog/e-commerce/

What about a Package diagram or a Component diagram?

I think for your particular case the Package diagram would be quite a good fit.

There is no UML diagram for this.