What is the difference between a flow chart and a UML activity diagram?

Question

I know that an activity diagram is:

1. More simple;
2. More standardized;
3. Support concurrent flows.

compared to a flow chart.

But what are the possible reasons for using an activity diagram instead of a flow chart apart from those mentioned above?

Oversupply

Answer 1

An activity diagram is not simpler than a flow chart. A flow chart is a simpler (earlier) version of an Activity Diagram.

Flow charts were invented at least 20 years earlier and are commonly used by non-programmers to document workflows. Any business process where people have to make decisions can be described as a flow chart. So, for example, a clerk making decisions about how to file complicated information might have a flow chart on the wall.

Because a flow chart is a subset of an activity diagram, there's actually no decision to make. A flow chart naturally grows into an activity diagram if you need to add more complex descriptions.

Sparx have a good explanation of the range of things you can describe in an Activity Diagram

Futurism

This doesn't mention the similarity of UML 2 activity diagrams to colored Petri nets. I was going to answer, but didn't have the info handy. – Trisomic

@JimL I guess that state charts are more related to Petri nets. And AD are another descendant. I don't have a source of my truth, though ;-) – Coupon

You say a flow chart is a subset of an activity diagram, user2864740 says an activity diagram is a subset of a flowchart. Personally I think the latter, as you've said yourself that flow charts predated activity diagrams - how can flow charts be a type of activity diagrams if the latter came later? – Earnestineearnings

A flow chart is a "subset" of an activity diagram because it has simpler semantics. Activity Diagrams were created in UML to fill the same role. – Futurism

Answer 2

A UML Activity Diagram is a type of "flowchart" .. in UML, with bells and whistles. There is no such thing as a "UML Flowchart". If using UML it is an Activity Diagram. If using something else, then something else is being used.

[UML] Activity diagrams are graphical representations of workflows of stepwise activities and actions with support for choice, iteration and concurrency ..

.. Activity diagrams may be regarded as a form of flowchart.

For better or worse, UML is a standardization. This is nice because it is well, "standardized", but also means that it is not appropriate for all tasks: the chosen "flowchart" model (and extensions thereof) might be a better fit for a particular problem/domain.

Profligate

Is this answer almost 15 years out of date, for UML 1? – Trisomic

The first link says UML 1. – Trisomic

"A UML Activity DIagram is a type of flowchart" Isn't it the opposite? Meaning, a flowchart is a type of a UML Acitivity Diagram? – Shikari

Answer 3

An activity diagram assigns responsibilities to the objects involved in collaboration using swim lanes. So the diagram clearly shows the work to be done by each object in collaboration.

Budd

Answer 4

Both flowcharts and activity diagrams are used to show workflow but the activity diagram has a provision for assigning responsibility to the objects with the help of the swim lane concept.

Budd