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Stefano Burigat and Luca Chittaro
of the traveled geographical area and contain yellow 2.5D arrows that are meant to
simplify the user’s understanding of the direction to follow.
In the third interface (Arrows + Pictures), the map has been replaced by large
black arrows (see Fig. 12.12(c)) that indicate the direction to follow. The behavior
is similar to the Map + Pictures interface. To determine which direction the user is
facing when moving we exploit the succession of position points provided by the
GPS and present the appropriate arrows according to the path the user should follow.
The results of the evaluation (described in detail in [12]) show that combining
a map with pictures that indicate the direction to follow or removing the map completely and replacing it with a combination of directional arrows and pictures significantly improve user’s navigation times with respect to the traditional map condition.
This is likely due to the fact that it is more difficult to understand the correct direction to follow with a map (even if the map is forward-up) than with more explicit
picture-based indications. Using pictures provides quite good navigational support,
because it simplifies the visual recognition of landmarks, and it has the additional
advantage of depending only weakly on the actual direction of the user, thus being
useful even when position and orientation information are inaccurate. This result is
also confirmed by users’ comments about the feeling of disorientation sometimes due
to the use of the map. Moreover, while both approaches exploiting pictures allowed
users to obtain a similar performance, the solution combining pictures and map was
highly preferred because it provided a higher amount of information compared to the
solution exploiting pictures and arrows.
12.4 Supporting User’s Decisions in the Field Through
Geographical Data Visualization and Visual Queries
Navigation is only one, albeit important, of the user’s tasks in the field that can take
advantage of the visualization of geographical data on mobile devices. In particular,
up-to-date geographical data can be used by different categories of users to properly support their decisions. For example, firefighters and first-responders can use
accurate geographical information while managing the impact of disasters to take
decisions to evacuate residents, change management tactics, inform other crews by
updating the set of available data on the disaster. Ecologists can employ geographical data to determine the best location to perform observations of animal or plant
species and collect data about individuals. Utilities maintenance personnel may accurately locate equipment in the field and update information about its status.
All these activities require users to gain access to geographical data visualizations
in the field as well as to manipulate them by modifying features, collect new data,
take geo-referenced measurements. Specific mobile GIS (geographical information
system) applications are usually devoted to this purpose.
With respect to geographical data visualization, mobile GIS applications are able
to display both raster and vector data and manage different geographical features
associated with a geographical area (e.g. roads, buildings, boundaries, trees) as separate layers so that users can display only the data they are interested in. Figure 12.13
Stefano Burigat and Luca Chittaro
of the traveled geographical area and contain yellow 2.5D arrows that are meant to
simplify the user’s understanding of the direction to follow.
In the third interface (Arrows + Pictures), the map has been replaced by large
black arrows (see Fig. 12.12(c)) that indicate the direction to follow. The behavior
is similar to the Map + Pictures interface. To determine which direction the user is
facing when moving we exploit the succession of position points provided by the
GPS and present the appropriate arrows according to the path the user should follow.
The results of the evaluation (described in detail in [12]) show that combining
a map with pictures that indicate the direction to follow or removing the map completely and replacing it with a combination of directional arrows and pictures significantly improve user’s navigation times with respect to the traditional map condition.
This is likely due to the fact that it is more difficult to understand the correct direction to follow with a map (even if the map is forward-up) than with more explicit
picture-based indications. Using pictures provides quite good navigational support,
because it simplifies the visual recognition of landmarks, and it has the additional
advantage of depending only weakly on the actual direction of the user, thus being
useful even when position and orientation information are inaccurate. This result is
also confirmed by users’ comments about the feeling of disorientation sometimes due
to the use of the map. Moreover, while both approaches exploiting pictures allowed
users to obtain a similar performance, the solution combining pictures and map was
highly preferred because it provided a higher amount of information compared to the
solution exploiting pictures and arrows.
12.4 Supporting User’s Decisions in the Field Through
Geographical Data Visualization and Visual Queries
Navigation is only one, albeit important, of the user’s tasks in the field that can take
advantage of the visualization of geographical data on mobile devices. In particular,
up-to-date geographical data can be used by different categories of users to properly support their decisions. For example, firefighters and first-responders can use
accurate geographical information while managing the impact of disasters to take
decisions to evacuate residents, change management tactics, inform other crews by
updating the set of available data on the disaster. Ecologists can employ geographical data to determine the best location to perform observations of animal or plant
species and collect data about individuals. Utilities maintenance personnel may accurately locate equipment in the field and update information about its status.
All these activities require users to gain access to geographical data visualizations
in the field as well as to manipulate them by modifying features, collect new data,
take geo-referenced measurements. Specific mobile GIS (geographical information
system) applications are usually devoted to this purpose.
With respect to geographical data visualization, mobile GIS applications are able
to display both raster and vector data and manage different geographical features
associated with a geographical area (e.g. roads, buildings, boundaries, trees) as separate layers so that users can display only the data they are interested in. Figure 12.13