What is Data Visualization? How can it be explained through a visual diagram? Can data visualization be... visualized?
David McCandless answered this recursive issue on his impressive blog Information is Beautiful already a while ago, with a 4-layered vendiagram graph that combines the concepts of "Interestingness", "Function", "Form" and "Integrity".
More recently, FFunction attempted to simplify the depiction of data visualization further by proposing a classic 3-layered vendiagram that mash the areas: "Information" , "Design" and "Communication", with its many intermediate steps.
It actually does not necessarily stop there: we proposed back in 2007 (PDF), the combination of "Aesthetics", "Data" and "Interaction".
You can compare the three approaches below.
Are there more models around? Do you have any preferences?