Animation is a "graphic art that occurs in time" (Baecker and
Small 1990). It is a dynamic visual statement that evolves through movement
or change in the display. In cartography, the most important aspect of animation
is that it depicts something that would not be evident if the maps were
viewed individually. In a sense, what happens between each frame is more
important than what exists on each frame (Peterson 1995, 48). In practice
animation is creating the illusion of change by rapidly displaying a series
of single frames (Roncarelli 1988). A common example would be the movement
of a cartoon character against a background. Movement can also be interpreted
as the change in the perspective of the observer as the figure remains still.
The variables of animation include both graphical manipulations and sound.
A distinction can be made between primary and secondary components of an
animation. The primary elements make the animation and the secondary elements,
like sound, accentuate the animation. The graphical variables of animation
include (after Hayward, p. 9):
- 1. Size-
- The size of an area on a map may be changed to show changes in value.
For example, the sizes of countries are made proportionally larger or smaller
to depict the amount of oil or coal reserves. An animation can be used to
transform the map of oil reserves into the map of coal reserves to show
the differences in location of the reserves.
- 2. Shape-
- An area on a map can be made to change in shape. The shape (and size)
of Greenland varies as a result of the influence of a map projection. An
animation can be used to blend between the two shapes to accentuate the
effect of the different projections.
- 3. Position-
- A dot is moved across the map to show change in location. For example,
the center of population for the United States has moved consistently to
the west, and more recently to the south. An animation can be used to depict
this movement through time.
- 4. Speed-
- The speed of movement varies to accentuate the rate of change as,
for example, with an animation that depicts the movement in the center of
population for the United States.
- 5. Viewpoint-
- A change in the angle of view, could be used to accentuate a particular
part of the map as part of an animation. An animation of population change
in the United States may use a viewing angle that focuses attention on the
western and southern states where significant increases in population have
- 6. Distance-
- A change in the proximity of the viewer to the scene, as in the case
of a perspective view. In cartography the distance variable may be interpreted
as a change in scale.
- 7. Scene-
- The use of the visual effects of fade, mix, and wipe to indicate a
transition in an animation from one subject to another.
- 8. Texture, Pattern, Shading, Color-
- Graphic variables that may depict a change in perspective for a three-dimensional
object. These may also be used to "flash" a part of the map to
accentuate a feature.
Magnenat-Thalman, et. al. (1990), effectively categorize these variables
by making a distinction between animation objects and graphic objects.
The graphic objects are the carriers of information and they can
be described with both geometric (size, shape, position) and graphic (texture,
pattern, shading, color) characteristics.
The camera defines the point and the angle of view (viewpoint). It
can be described with the following variables: vertical or horizontal position,
distance to the graphic object, angle of orientation and direction.
The light source gives form to three dimensional objects. It can
be described with the following characteristics: position, angle, form,
color, and, intensity.
Animation objects may be dynamic or static. Other visual components of the
animation include the scene and the sequence. The scene is the structured
positioning of animation objects. The sequence is the structured presentation
of changing scenes. Sequences can be tied together with transition effects.