Geography Reference
In-Depth Information
In a different study the same authors [32] deal with a generic evaluation approach
combining theory and data-driven methods based on sequence similarity analysis. The
approach systematically studies users' visual interaction strategies when using highly
interactive map interfaces. The result was that the participants generally follow a sequence
that agrees with the hypothetical sequence representing user's strategies.
Another application of eye-tracking in cartography appears in the study of Opach and
Nossum [33] where authors have explored the suitability of eye-tracking on two different
semistatic and traditional cartographic animations of temperature and weather. Contrary to
the author's previous web based experiment, analysis of the eye-tracking data revealed that
the viewing behaviour were surprisingly similar. Three of the metrics used (fixation counts,
observation length and time to first fixation) indicated very similar viewing strategies and
behaviour during viewing different kind of cartography animations.
Fuhrman, Tamir and Komogortsev [34] have dealt with an assumption that three-
dimensional topographic maps provide more effective route planning, navigation,
orientation, and way-finding results than traditional two-dimensional representations. The
eye-tracking metrics analysis indicates with a high statistical level of confidence that three-
dimensional holographic maps enable more efficient route planning.
Popelka and Brychtova [35] used eye-tracking together with questionnaire investigation for
evaluation user's attitudes toward interactive methods of virtual geovisualisation of changes
in the city built-up area. Five approaches of visualization were assessed - textual description
of changes, comparison of historical and recent pictures or photos, overlaying historical
maps over the orthophoto, enhanced visualization of historical map in large scale using the
third dimension and photorealistic 3D models of the same area in different ages.
Technologies and methods of eye-tracking have not yet been fully utilized in cartography,
even though the possibilities are wide. Cartographic research in the field of eye-tracking
currently focuses explicitly on improving the user quality of maps. Future potential expansion
of eye-tracking technology can be seen in the activity of the International Cartographic
Association, especially the Commission on Use and User Issues [36] and the newly established
Commission on Cognitive Issues in Geographic Information Visualization [37].
4. Methods of eye-tracking data visualization
Results of eye-tracking measurements are presented as a text file containing a timestamp
and a number of specifications describing coordinates of the point of regard, the pupil size,
the angle of the eye position etc. First of all, it is necessary to classify the data, with a
specified algorithm, as fixations and saccades (see chapter Eye movements and algorithms
of their detection). Then, the data are even visualized in a suitable way, or can be
statistically analysed.
There are several basic methods of the eye-tracking data visualization. Holmqvist et al. [20]
present the main techniques of gaze data visualization as follows: ScanPath (GazePlot),
Attention (Heat) maps and the AOI (Area of Interest) Analysis.
