Communication Aspects: How Landmarks Enrich the Communication Between Human and Machine - Landmarks: GIScience for Intelligent Services - page 192

these arguments. We will discuss usability studies and other forms of evaluation
that explicitly looked at the benefits of incorporating landmarks. A word of warning
in the beginning though: not all is well yet in the realm of landmark-based services.
The following studies focus on aspects of landmark production. They are inter-
ested in how well (or how much better) users understand a service's communication
output if this service employs landmarks. Most of them look at verbal production,
but there is some work done on graphical landmark production as well.
Let us start with a requirement analysis. Burnett and his group have done a range
of such studies as well as some work on human factors in landmark use (e.g., [ 8 , 51 ] )
in the context of in-car and pedestrian navigation systems.
In the 1990s studies compared having a passenger providing instructions vs.
using a car navigation system. A passenger who has detailed route knowledge
and provides clear and timely instructions arguably presents the ideal situation.
Compared to this, drivers using a navigation system made more navigation errors,
took longer to complete a route, spent less time looking on the road or in the mirrors,
rated their mental workload to be higher, and were rated by an expert to have lower
quality of driving [ 9 , 27 ] . Based on these studies and other findings, Burnett [ 8 ] listed
several reasons why navigation systems should include references to landmarks
reflecting the arguments we have made: (1) Landmarks are consistent with basic
human navigation strategies; (2) landmarks are valued by drivers; (3) landmarks are
effective and efficient in navigation tasks; (4) landmarks increase user satisfaction.
Argument (1) has been widely discussed in the topic. Regarding Argument (2),
for example, a survey of 1,158 UK drivers found out that landmarks are the
second most popular information type (after left-right information) that participants
would want from their passengers helping in navigation [ 11 ] . Burnett's group found
that participants either identified landmarks as crucial information in navigation
situations or produced landmark references to support others in navigation tasks,
depending on the condition tested and consistent with what we have discussed
earlier [ 10 , 51 ] . Arguments (3) and (4) will be discussed in more detail in the
following—that is what this section is all about.
In an evaluation study testing pedestrian navigation instructions [ 59 ] , participants
either received instructions relying on distances and street names, or enhanced
instructions with landmark references (similar to those of WhereIs). Ross et al.
found that participants receiving enhanced instructions were significantly more
confident in taking the right decisions at decision points and, indeed, also made
fewer navigation errors compared to those receiving the basic instructions. Their
study clearly makes a case for the inclusion of landmarks.
The Kiosk system [ 16 ] proved to be successful in guiding wayfinders as well.
As already mentioned in Sect. 6.3.1 the rate of parsed utterances is rather low with
only about 17 %. However, the keyword spotter manages to cope for this and detects
useful keywords in 80 % of the utterances (leaving only 3 % of unparsed utterances).
In the Kiosk system evaluation, 26 participants, who were mostly unfamiliar
with the environment, had to find their way to six different locations in a university
building after negotiating with the kiosk how to get there. Given the high detection
rate for keywords, only short dialogs were needed for users to receive the required