Geography Reference
In-Depth Information
6.2
Producing Landmarks
In their initial paper on landmark identification, Raubal and Winter [ 54 ] have
already suggested a formal notation for including landmarks into route directions.
Approaches for producing landmarks are to this day predominantly developed for
enriching route directions with landmarks. Most notably, the Australian routing
service WhereIs augments its route directions with landmark references that are
derived from an external collection of POIs (see Chap. 5 ) .
As a little exercise you may try to recreate yourself the route described in
above dialog. The best route we could achieve on WhereIs contains some
unnecessary turns and loops and, thus, results in 22 instruction steps. This is
clearly much more complicated than the human dialog. For that reason, we
will not use this particular route for the following example.
6.2.1
Producing Verbal Landmark References
Commercial routing services usually generate their instructions using some pre-
defined templates with little linguistic variation. The same holds for WhereIs,
which uses a template of the form “< TURN ACTION onto STREET NAME at
POI NAME >” to incorporate landmark references into the generated instructions.
For example, when calculating directions from the Melbourne Exhibition Centre
(on Normanby Rd, Southbank) to The University of Melbourne (156-292 Grattan
St, Parkville) , 1 five (out of the 11) instructions contain a reference to a POI
landmark: “At the roundabout, take the 1st exit onto Peel St, West Melbourne at
Queen Victoria Market ”; “Veer left onto Elisabeth St, Melbourne at Public Bar
Hotel ”; “At the roundabout take the 3rd exit onto Elisabeth St, Melbourne at Dental
Hospital ”; “Turn right onto Grattan St, Melbourne at Royal Melbourne Hospital ”;
“Turn left onto UNNAMED road after Barry St, Carlton at The University of
Melbourne ”. As you can see, these instructions utilize large, prominent buildings as
landmarks, which are easy for wayfinders to identify. At the same time the generated
instructions are very monotonous, especially given that those instructions without
landmark references (not printed here) look very much the same without the “at”
part.
In research, there have been several attempts of breaking up these monotonous
directions with more variation, using methods from natural language generation
(NLG). Dale et al. [ 17 ] , for example, argued for a more natural sentence structure
1 Like most routing services, WhereIs requires address information to actually calculate a route.
 
 
 
 
 
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