"The purpose of this article is to provide a review of the research on a... form of knowledge representation, the knowledge map, and to point to areas of future research... and to some... practical implications... Other forms of graphical representation such as concept mapping... have been widely used in science education research... Knowledge maps are node-link representations in which ideas are located in nodes and connected to other related ideas through a series of labeled links. They differ from other similar representations such as mind maps, concept maps, and graphic organizers in the deliberate use of a common set of labeled links that connect ideas. Some links are domain specific (e.g., function is very useful for some topic domains...) whereas other links (e.g., part) are more broadly used. Links have arrowheads to indicate the direction of the relationship between ideas."