Communication Aspects: How Landmarks Enrich the Communication Between Human and Machine - Landmarks: GIScience for Intelligent Services - page 177

Tabl e 6. 1 Example output of
the CORAL system;
from [ 17 ]

Start at Parbury Lane
Follow Parbury Lane until you reach the end
Take a right
Follow Lower Fort Street for 30 m
Turn to the left at George Street
Follow George Street until you reach your destination

(or more) messages are merged. Most typically, this is a PATH C POINT (e.g.,
'follow the road until the roundabout') or POINT C DIRECTION (e.g., 'turn left at
the gas station') combination, but other combinations are possible as well. The latter
part of the micro-planning phase is generating referring expressions—including
selection of the reference noun (or pronoun, or other construct) used to describe
an intended object, such as an intersection or landmark. Following the principles
of relevance [ 33 ] , the CORAL system tries to be as specific as needed, following
the three principles of sensitivity, adequacy, and efficiency. It in turn uses as a
reference alternatively either a landmark that is at or close to an intersection, the
type of intersection (e.g., T-intersection or roundabout), the name of the immediately
preceding intersection, or the name of the intersecting street.
Finally, the surface realizer phase maps the semantic specifications into actual
sentences, i.e., into (grammatically correct) natural language. An example output of
the CORAL system is shown in Table 6.1 ; this example is taken from [ 17 ] .
As you can see, these instructions have some more linguistic variation than the
WhereIs directions discussed above (on p. 179 ) . For example, turns are described by
stating 'take a right' or 'turn to the left'. Curiously enough however, the particular
example provided by Dale et al. does not contain any landmark references, with an
exception of the structural landmark 'the end of the road' [ 42 ] .
Another system that aims for variation in the generated route directions is an
information kiosk developed at the University of Bremen, Germany [ 16 ] . While set
in an indoor scenario, it makes explicit use of landmark references and is based on
some of the methods discussed in Chap. 5 . There is no principle reason why it would
not work in an outdoor setting as well. Figure 6.2 shows an overview of the pipeline
architecture employed in the kiosk system. For now we are only interested in the
bottom part, i.e., the pathway starting at the 'spatial data' box and leading to the
'user' box. We will discuss the top part in the next section.
Except for being a dialog system, i.e., enabling some synchronous, co-presence
user interaction, the system's approach to producing route directions is similar
to the CORAL system. The kiosk system starts by calculating a route between
the kiosk itself, which always is the origin since users are standing in front of
the computer running the kiosk software, and the requested destination. Next, the
instructions required to successfully navigate this route are determined. To this
end, a computational process called G UARD (Generation of Unambiguous, Adapted
Route Directions) [ 57 ] is employed. G UARD unambiguously describes a specific