In most systems approaches mapping is used to describe systems. But these visualizations go far beyond the explanatory intention in normal information visualization. They tend to produce very particular images of the world. I claim that most of these models tend to "over-design" the topic they try to describe or simulate. Very strong conventions like the node and the arrow, an urge for consistency of the model, covering comparable entities only, leaving out "wild" information that does not fit in and defining all nodes in a certain way, e.g. as variables, tend to shoehorn the conception of the real world phenomenon at stake into a very restrained model.
GIGA-maps are wicked artifacts. In contrast to the other types of mapping their intention is to explode the issue at hand as wide and deep as possible, to increase its complexity, to layer different types of information that normally are regarded as categorically separated and to seek out how they are related. GIGA-maps are process tools, aimed at helping the designer to reach a more inclusive and holistic conception of the task. They will only have communicative value in their final form. They are only fully understood by the people who create them. They are participatory and creative devices. They will never be consistent or finalized. They tend to resist attempts of systematization and categorization, though we constantly try to develop e.g. libraries of types of maps and relations. (see forthcoming papers).
We think GIGA-maps do something different than other types of information visualization and that this approach is valuable for real life problems and systems thinking in design.