Visualization of what data represents

I know there has been much discussion about data visualization here,
but I ran into a need this week to represent not the data, but rather
what makes up the data. I.e., data point combinations or collections
of processes that produce the information that we are looking at.
The goal being to help understand which data is truly meaningful in
the context of discussion and for decision-making.

Does anyone have any tips or examples to point to? A colleague and I
quickly took a basic app work-flow in powerpoint and overlaid shapes
to group points and processes, but I found this crude and
non-scalable.

Ideas?

ph