maybe some sort of directed graph.

for example one thing I might want to have to describe visualization methods would be what graphical elements would be important to it.

In the case of the periodic table an important graphical element would be color (the color used carries date), an unimportant one would be typography.

this is obviously just thinking aloud here.

perhaps also some visualization methods would benefit by reference to their creators. sparklines for example. So it seems to me a graph of some sort would be useful.