Geography Reference
In-Depth Information
Animation has it roots in the Latin word
animare
, in English, 'bring to life'. Animation
is not to be confused with film or video movies. Animations are defined as sequences of
static graphic depictions (frames), the graphic content of which, when shown in rapid suc-
cession (typically 24-30 frames per second), begins moving in a fluid motion. The use of
animated maps spans the spectrum of disseminating spatial knowledge to a wide audience
(e.g. animated weather map loops on television) to data exploration for knowledge discov-
ery by experts (e.g. highly interactive exploratory spatial data analysis tools for scientists).
Animated maps have become increasingly popular in recent years because they congruently
represent the passage of time with changing graphic displays (or maps). With Google Earth
or similar virtual-globe interfaces that can render rich, immersive three-dimensional maps
in real-time, the dynamic change of one's point of view or geometric perspective on a three-
dimensional landscape has become as easy as one mouse click. However, this technology goes
beyond just virtually exploring the surface of the Earth: expert users of animated maps can
now explore 'attribute space' using the same kind of techniques developed to explore 'geo-
graphic space', for example, when cycling through different themes of a geographic dataset, or
by moving along a timeline that represents ordered data values of a certain variable of interest.
An example of this is Peterson's (1995, pp. 50-51) non-temporal animation
1
depicting
the percentage of births to mothers under the age of 20 for the United States. The first frame
in the animation is a two-class map and the last frame is a seven-class map. The legend is
represented as a histogram with bars indicating the number of observations in each category.
Regardless of the map-use goal, unlike static maps that do not change, the individual
frames of an animated map are on-screen briefly and there is little time to examine fine
details (Monmonier, 1994; Harrower, 2003). In other words, there are obvious cognitive
and perceptual limits that must be understood and used to inform map design. We believe
that exceeding these limits - which is easy to do with today's massive and complex dataset
coupled with powerful computer graphic cards - is likely to leave the user frustrated or unsure
of what they have seen. Since our visual memory has limits (Marr, 1982) we will simply not
see the finer details in the animation, and only the most general patterns and clusters will be
noticed (Dorling, 1992). Basic map-reading tasks, such as comparing colours on a map with
those on a legend, become significantly more difficult when the map is constantly changing
and thus 'the compression of time as well as space in dynamic cartography poses new
problems requiring the recasting, if not rethinking, or the principles of map generalization'
(Monmonier, 1996, p. 96).
Their fleeting nature combined with the problem of split attention suggests, then, that
the primary utility of animated maps is to not to emphasize specific rates for specific places,
but rather to highlight the net effect of the frames when run rapidly in sequence and to
gain an overall perspective of the data (Dorling, 1992). According to Ogao and Kraak (2002,
p. 23), 'animations enable one to deal with real world processes as a whole rather than
as instances of time. This ability, therefore, makes them intuitively effective in conveying
dynamic environment phenomena'. Unlike static maps, animated maps seem especially
suited to emphasizing the change between moments (Peterson, 1995) and static maps are
often insufficient for the task of representing time because they do not directly represent - or
foster hypotheses about - geographic behaviours or processes. Because animated maps can
1
Examples
of
non-temporal
map
animations
are
available
on
the
web
at:
http://maps.unomaha.
edu/books/IACart/book.html#ANI
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