Introduction:What Landmarks Are, and Why They Are Important - Landmarks: GIScience for Intelligent Services - page 14

For example, markers on a genome may be important elements to conceptualize
and structure their spatial representation. But even if science speaks of 'mapping
the genome', and the scientists structure their mental representations of the genome
by these markers, mental representations of space at this scale are not directly
accessible to the experience of human senses.
It is likely that animals also experience landmarks as geographic objects
structuring their mental representations of space. Rich neuroscientific and cognitive
literature suggests that spatial abilities are among those where insights learned
from animals can be transferred to human cognition. However, the animals'
embodied experience of environments is different. For example, ants, honey-
bees or rats—thoroughly studied animals for their orientation and wayfinding
skills—navigate at completely different scales. Hence, this topic will generally not
expand on animal spatial cognition.
Robots are another domain of knowledge where landmarks play an immi-
nent role. Robots are capable of simultaneous localization and mapping (SLAM,
e.g., [ 44 ] ), learning an unknown or updating a known environment through their
sensors. For them landmarks are stable and easily identifiable external points of
reference, sometimes artificial tags put out in the environment, sometimes objects
of the nature we consider in this topic. Since machine sensors, machine mapping
and machine reasoning are qualitatively different from human embodied experience,
memorization and reasoning, this topic will also not address landmarks in artificial
systems.
However, in addition to the use of landmarks in other domains we are also
going to differentiate landmarks from related concepts, especially where terms are
sometimes confused in common language. In the following we discuss places ,
points of interest , icons ,and metaphorical landmarks .

1.2.1 Places

Landmarks are points of reference in mental spatial representations. Their function
in mental representations is to locate other objects. This function establishes a
connection to place , which is another geographic concept structuring space, and
perhaps one that is even more elusive than landmarks [ 19 , 35 ] .
This elusiveness of place emerges from the tension between the informal world
of human cognition and discourse that deals with objects on one side, and on the
other side a continuous physical world “out there” that does not come by objects in
the first instance [ 10 ] . In addition the term has been used with different meanings.
Gärling et al. ([ 17 ] , p. 148f) said: “Place is a concept that is rich in meaning and
difficult to define”, and that is only rephrasing Aristotle: “The question, what is
place? presents many difficulties” ( [ 2 ] , IV/1).
However, in a book on landmarks we can be more specific. A purely philosophic
position was taken by Aristotle, who says later in his Physics ([ 2 ] , IV/4):