In any novel environment, human wayfinding involves the recognition and appreciation of common representations and information obtained from other human beings. The former includes signs, maps, descriptions, and images. With the help of these sources, human beings begin to explore unknown areas and integrate perceptual stimuli into an internal, consistent representation of the environment. Coined by Tolman, these internal representations are called cognitive maps [98].
The term cognitive map should not be taken as anything more than a metaphor applied to what is really an internal representation that may be composed of any one of a number of things [29]. Downs and Stea referred to the cognitive map as ``an incomplete, segmented, metrically distorted representation, with relational accuracy, both spatially and non-spatially varying within and across regions'' [31]. Cartographic maps are designed with the intent of presenting the environment in as objective a manner as possible with some cartographic license taken by the cartographer. On the other hand, the purpose of the cognitive map is to integrate and apply environmental information using a representation that is built inside the head for the individual's personal use.
As an individual's familiarity with an area increases, the use of the internal cognitive map gradually replaces the reliance on external sources of information [45, pp. 34-5]. For example, after having walked from the school to the train station numerous times, the tracks (which run in parallel to the last section of the path) become less of a common representation of the vicinity of the train station, but more of an anticipated landmark used in the process of localization within the cognitive map (see section 3.1.1). Traveling through an environment is commonly recognized as the way humans most frequently acquire spatial knowledge [45, p. 19].
Cognitive maps store conscious perceptions, but also automatic (subconscious) encodings17 of spatial relations to help determine one's current position, where specific objects are in surrounding space, and how to get from one place to another. This type of internal representation is also known as a subjective structure, a mental map, a cognitive collage [99], a cognitive configuration [41], and an internal GIS (geographical information system) [47]. Golledge partitions the acquisition and use of geometric entities (points, lines, areas, surfaces) within a cognitive map into quantitative and qualitative terms. Quantitatively, these entities provide a basis for (mental) geometric and trigonometric manipulation of the information. When assessed qualitatively, information pertaining to, for instance, topological relations, order, inclusion, and exclusion can be extracted [43].
Cognitive maps are representations of sets of connected places, which are systematically related by groups of spatial transformation rules [75, p. 86]. Despite the name, cognitive maps are not similar to cartographic maps. Cognitive representations need not bear a one-to-one correspondence with their counterparts in physical space, and evidence shows that cognitive maps can violate basic geometric axioms (see, i.e., Rivizzigno 1976, cited in [46]). Furthermore, Golledge suggests that if cognitive maps were cartographically founded, map reading skills would be required prior to the use of cognitive maps [45, p. 36]. However, studies have shown the skill of map reading to be acquired in children development well after the child exhibited use of a cognitive map [30].
Within the study of cognitive maps two specific types of cognitive structures have been identified. The literature supports the existence of both, a route-based cognitive map and a survey level cognitive map, the latter being related to survey level knowledge and the ability to abstract spatial information about the environment [29]. Although landmark knowledge (see section 3.1.2) is inherently incorporated into these two cognitive representations, there is no specifically landmark based cognitive map [47].