Have a look at this short talk by David McCandless on data visualization:
There are a number of interesting things for argumentation theorists to think about here. For one, if McCandless is right then clearly what he says is wind in the sails for those who rate argument diagramming highly among our various tools of analysis.
While watching this presentation I also found myself wondering if McCandless’ technique might provide aid and comfort to the cause of those who believe in visual arguments too. To be clear, I don’t think that any of the visuals he presents here is an argument. He makes visual statements, sure, and at times draws inferences from them, but that would make his arguments (in my book at least) arguments with visual elements–not visual arguments per se. Still I found myself wondering if maybe purely visual arguments might be a possible innovation that could come from the kind of work McCandless is doing, somewhere down the line.