Geography Reference
In-Depth Information
Somewhat surprising is the frequency that the
filter
operator is implemented
(21/25; 84 %), or the ability to adjust the visualization to only show map features
that match one or more user-defined conditions, as compared to
search
(13/25;
52 %), or the ability to identify a single location or map feature of interest. The
search operator is more common in general use applications for which users have a
single, concrete task, and therefore need a single entry point (i.e., a
) for
locating the feature of interest; on the other hand, the filter operator is more
common in expert use applications for which the users have abstract or undefined
tasks and require iterative exploration through small changes to filtering parame-
ters. Many of the visualization tools use the filter operator to adjust the water level.
The one evaluated visualization tool specific to the Great Lakes, Green Bay
LakeViz, supports filtering from
'
search box
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12 to +9 ft based on variation in flood gauge
data from 1996-to-present. When search is implemented, it is provided to reposition
the map to a particular location, not a particular map feature or water level.
A small majority or large minority of visualization tools implement the work
operators
calculate
(12/25; 44 %) and
resymbolize
(8/25; 32 %). The calculate
operator allows users to derive custom information about map features of interest.
Implementations include the dynamic calculation of total area impacted by a
hypothetical flood (5/25; 20 %), a spatial measurement tool (4/25; 16 %), and the
dynamic calculation of unique land use types impacted by a hypothetical flood
(3/25; 12 %). The resymbolize operator allows the user to set or change a design
parameter of the map representation without changing the features displayed on the
map (as with the filter operator). The resymbolize operator exclusively is provided
to adjust the transparency of overlay context layers. Finally, the arrange operator is
implemented in four (16 %) of the visualization tools, allowing the user to adjust the
position of map elements and interface functionality to avoid overlap with the map.
Importantly, the Fig.
5
analysis reveals several opportunities for the Lake Level
Viewer that could set it apart from other water level visualization tools. First, none
of the visualization tools implement the
reexpress
operator, which produces a new
visualization of the same information, effectively
. View-
ing the inundated or exposed land from a profile view along a user-defined transect,
for instance, is one way in which the visualization can be reexpressed to generate
new insight. Second, only the SLAMM View tool implements the
sequence
oper-
ator, allowing for creation and comparison of side-by-side small multiples of
different future scenarios (Tufte
1983
). However, no tool implements the sequence
operator to control animations of the waterline or flood extent. Finally, while the
export
enabling operator is commonly supported (17/25; 68 %) as a way to share the
link of the current map view, the implementation of additional enabling operators
may improve analytical work across use sessions. In particular, the
annotate
operator could support collaborative decision making, allowing users to externalize
their thoughts into the map display for sharing with their project team.
showing it another way
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