Cognitive Aspects: How People Perceive, Memorize, Think and Talk About Landmarks - Landmarks: GIScience for Intelligent Services - page 67

develop first. One challenge lies in the ambiguity about the orientation of the body,
where chest, head and viewing direction can be, and frequently are, not aligned.
If the body is moving, then the heading direction can be non-aligned with any of
the prior ones. Another challenge, and a more significant one, lies in the body's
mobility, which requires constant updating of a representation of all the relationships
of the body with the objects in the environment. This updating is actually much
more costly than maintaining an allocentric, stable representation of the location
of stationary objects and only updating the body's location and orientation in
this representation. I can mentally visualize: “The car is parked in front of the
church”, which has no reference to my body at all, but instead refers to the inherent
orientation of the church, which has a front side by design. When I move or turn,
the relationship between car and church remains stable.
Updating my location in an allocentric frame of reference can happen in
two ways. One was mentioned before, path integration, sometimes called dead-
reckoning . This updating process through path integration is independent of the
configuration of objects around. Path integration provides an update only with
respect to an initial location. Loomis et al. investigated the ability of path integration
by homing experiments with either blind or blind-folded humans [ 125 ] . Similarly
to technical dead-reckoning systems, which are equipped with inertia sensors, path
integration quickly accumulates error.
The other updating mechanism is piloting , orientation by recognizing landmarks
in the world, and establishing the own body's relationship to these landmarks in
their known configurations. Piloting, therefore, has no accumulation of errors. But
it relies on the presence of recognizable landmarks in the proximity. Unavoidably
piloting has to deal with gaps between experiencing these landmarks, and path
integration can help bridging these gaps.
As early as 1913 Trowbridge postulated two frames of reference, one that
he called egocentric but actually used cardinal directions instead of body
orientation, and a domicentric that puts home (lat. domus )inthecenter[ 218 ] .
He thought within range of home mental spatial representations will be
domicentric, and what goes beyond will be computed by polar coordinates, a
form of path integration in the frame of the orientation of the Earth, and hence
an allocentric perspective. Trowbridge must be lauded for postulating a mental
spatial representation so early in the twentieth century. His classification is no
longer supported, although our thought experiment (Chap. 2 ) used 'home' as
the first point of reference.
The thought experiment (Chap. 2 ) had used 'home' as an allocentric first point
of reference, later replaced by a pole together with a reference direction (see also
Fig. 3.7 ) . But with more and more landmarks in the experiment's environment a
single datum point can be traded for configurations of landmarks, at least for local