Communication Aspects: How Landmarks Enrich the Communication Between Human and Machine - Landmarks: GIScience for Intelligent Services - page 188

The SpaceBook system uses commercial software for parsing natural language
input as well as for speech generation. An interaction manager keeps track of the
geographic context and the dialog history to resolve anaphoric references , 8 among
others. Questions related to the navigation process are answered by computations
within the system (e.g., distances between locations). Touristic questions are
answered by a textual lookup from the Gazetteer of Scotland, Wikipedia 9 and
Wo r d N e t . 10 A ranking mechanism, which was trained using machine learning
techniques, ranks candidate answers and the top candidate is presented to the user.
Since answers often involve fairly long text, they are provided piecewise and users
can interrupt their presentation anytime. Understanding what kind of question is
being asked is again achieved through machine learning, i.e., by training another
classifier using an annotated question corpus.

6.3.2 Understanding Graphical Landmarks

Not many interfaces exist allowing for spatial input in graphical form, let alone
graphical input related to landmarks. This may change in the (near) future with
the advent of smartphones with their advanced gesture input recognition. There has
been a long run of research on so called query by sketch [ 23 ] , however. Query by
sketch permits users to sketch (draw) a spatial query to request some information
from a service. Such sketches are first and foremost a sequence of pixels, which
may be grouped to lines (a geometric operation). These lines may then be further
grouped to represent some geographic objects (a semantic operation, even though
it will incorporate geometric sub-operations), such as streets, buildings, or labels.
Figure 6.6 shows a fictitious sample sketch map that is quite typical for how people
produce such maps in a communication act.
As discussed by Forbus et al. [ 28 ] it takes a big effort for a computational system
to understand sketches. The authors characterize the sketching ability of a system
as well as of its users along four dimensions: visual understanding , conceptual
understanding , language understanding , drawing skills .
Visual understanding refers to the ability of making sense of the 'ink' used
while sketching, i.e., how different line strokes form and how these line strokes
in turn may form more complex objects (so called 'glyphs'). Geometric operations
as mentioned above fall into this kind of understanding. Conceptual understand-
ing helps translating these objects into meaningful elements (such as streets or

8 Anaphoric references use some kind of deictic reference, usually a pronoun, to refer back to an
item mentioned before. For example, in 'St Peter is a large cathedral in Rome; it is home to the
Pope' 'it' is an anaphoric reference to St Peter.
9 http://www.wikipedia.org , last visited 8/1/2014.
10 http://wordnet.princeton.edu/ , last visited 8/1/2014.