268
Stefano Burigat and Luca Chittaro
Fig. 12.5. Variable-scale maps: a circular area (in the center) is shown in full detail, while the
remaining area is generalized and distorted to fit the available space [17]. Image courtesy Lars
Harrie, Lund University, SWE
(not necessarily the center of the map) while using a small scale and applying generalization and distortion operations to fit the remaining map area in the available
space (Fig. 12.5).
Unlike variable-scale maps, focus maps [39] are not based on distortion but on
subdividing a map into different regions of interest and displaying each region with
a different amount of detail according to its degree of interest. This is achieved by
using generalization and color. Map features lying inside regions with a high degree
of interest are less generalized than those inside regions with a low degree of interest.
Moreover, bright and shiny colors are used for the former regions, while softer and
duller shades of the same colors are used for the latter. As an application example,
regions of interest may comprise the region a user is currently in and, if the current
task involves movement, the regions the user is about to encounter. In this way, user’s
attention is directly drawn toward those regions that are currently most relevant, but
the other regions can still be used, for example, to help the users to locate and to
orient themselves.
Despite their capability to improve map visualization on small screens, Focus&Context techniques are unsuitable for users who need to use large undistorted
maps to perform spatial tasks involving distance measurements, such as first responders who need to identify locations of potential hazards in a building or view the
real-time location of other team members. To better support these users, one can
provide them with information to locate relevant objects even when they are offscreen. This is the approach followed by Baudisch and Rosenholtz [4] who propose
Halo a technique to visualize off-screen objects locations by surrounding them with
circles that are just large enough to reach into the border region of the display window. From the portion of the circle visualized on-screen, users can derive the offscreen location of the object located in the circle center. A user study has shown
that Halo enables users to complete map-based route planning tasks faster than a
Stefano Burigat and Luca Chittaro
Fig. 12.5. Variable-scale maps: a circular area (in the center) is shown in full detail, while the
remaining area is generalized and distorted to fit the available space [17]. Image courtesy Lars
Harrie, Lund University, SWE
(not necessarily the center of the map) while using a small scale and applying generalization and distortion operations to fit the remaining map area in the available
space (Fig. 12.5).
Unlike variable-scale maps, focus maps [39] are not based on distortion but on
subdividing a map into different regions of interest and displaying each region with
a different amount of detail according to its degree of interest. This is achieved by
using generalization and color. Map features lying inside regions with a high degree
of interest are less generalized than those inside regions with a low degree of interest.
Moreover, bright and shiny colors are used for the former regions, while softer and
duller shades of the same colors are used for the latter. As an application example,
regions of interest may comprise the region a user is currently in and, if the current
task involves movement, the regions the user is about to encounter. In this way, user’s
attention is directly drawn toward those regions that are currently most relevant, but
the other regions can still be used, for example, to help the users to locate and to
orient themselves.
Despite their capability to improve map visualization on small screens, Focus&Context techniques are unsuitable for users who need to use large undistorted
maps to perform spatial tasks involving distance measurements, such as first responders who need to identify locations of potential hazards in a building or view the
real-time location of other team members. To better support these users, one can
provide them with information to locate relevant objects even when they are offscreen. This is the approach followed by Baudisch and Rosenholtz [4] who propose
Halo a technique to visualize off-screen objects locations by surrounding them with
circles that are just large enough to reach into the border region of the display window. From the portion of the circle visualized on-screen, users can derive the offscreen location of the object located in the circle center. A user study has shown
that Halo enables users to complete map-based route planning tasks faster than a