Teaching Animated Cartography

Ferjan Ormeling

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Introduction

Now that they have animated maps at their disposal, now that they can actually show spatial developments, it seems incredible that cartographers have been able to do without for so long. They have known all along that in theory one's perceptory system was more attuned to moving stimuli than to static ones, that people actually have special sensors to detect motion - and still cartographers have hardly tried to animate their maps.
This was in tune with other kinds of representation - with graphic art, paintings, sculpture - there as well the advent of motion is recent, although earlier than in cartography: motion pictures have been with us for about a hundred years, mobile sculpture for 20, and video art for as long. Although animated maps have been discussed in cartographic literature since the 1970s, it is only about 5 years now that they are really being analysed. Just as the impact of graphical variables was studied for the first time systematically in the 1960s by Jacques Bertin, the research into motion variables and their impact upon our perception started only in 1990. This theoretical research is so new, that its results have not found their way yet to cartographic education - which it should as soon as possible, as it is the present generation of cartography students that will have to produce the animated maps society needs.
The impact of the computer on cartography and cartographic concepts has been a subject for discussion for long, even long before cartographic animation was an issue. But, as a matter of fact, it is animation which seems to be the most important aspect of the computer impact on cartography, both for cartographic cognition, analysis and communication of spatial data, just as GIS is for their analysis.
Under the influence of the digital revolution, MacEachren (in maceachren and taylor 1994 ) has defined maps as dynamic interactive spatial information tools. This presupposes an animation facility and that is why animation should be part of our educational programmes. What then should 'Teaching animated cartography' consist of? In my opinion there should be:
Every new item in cartography courses will be scrutinized for its contribution to the discipline, as the time available is limited, and the number of subjects useful for cartographers is already too large as it is. So, to account for the time taken away from other useful subjects, animated cartography should provide an obvious advantage in analysing and communicating spatial information. The deliberations of cartographers regarding animated maps, should therefore be more related to the effects of these animated maps, and these effects are only now being studied. Alexandra Koussoulakou proved by her work (1990) that at least animated maps convey information much faster than static maps. Slocum et al in that same year (1990) found no clear advantage of animated maps over sequenced maps regarding the ability to recall patterns. Koussoulakou and Kraak (1992) have found that animated maps do better only when the display time can be controlled by the users. At Utrecht University some work is being done (see contribution by Köbben in this volume) on tests on the perception characteristics of the temporal variables discerned by for instance DiBiase and MacEachren, but overall this still is only a minute beginning. Cartographers are still a far way off in answering questions as to the effects of their animated maps.
An animated map could be simulated by showing the audience some consecutive slides that together visualize Napoleon's attack on Russia in 1812. These slides might be taken from Millennium which, put on the fast forward mode, would show continuously all the changes on the political map, with a temporal resolution of one image for every month. Played fast forward this has the effect of animation.
When showing this sequence, the question would be what would make this presentation so much less convincing than the map of the same event by Joseph Minard (also used in DiBiase et al's argument 1992), produced in the 1840s and, albeit a flow diagram, still a static presentation? It will be this flow diagram that will stand out in one's memory, and not the animated one, because Minard's map is a synoptic view. It allows one to compare and by virtue of its static nature it can be more complex, adding the temperature component for instance. Cartographers have not yet tried to address the reasons for this difference in impact, and it is animated map use research that should come up with the answers.

Teaching the theory of animated mapping

In traditional cartography one could only just mimic or simulate movement - and map users would have to use their imagination, either for deducing the changes from one single map or by comparing a series of maps (see figure 1).

McCloud (1993) has indicated what mechanisms are at work in series of images to have them perceived as a continuous story. Closure and the 'gutter' between the images play an important role here. Now with animated mapping it is possible to give a real sense of motion - either by providing the sensation of moving oneself or by moving the object, or both, or by having the object subjected to change.
What makes maps be perceived as dynamic? Change, of course, but what makes one perceive change? Change in position in relation to reference points is one, change in texture/colour another. As time is an ordered variable, it can be rendered by ordinal visual variables, that is by differences in size, value or texture. This has been worked out by Bertin, and, though not universally accepted, it is used as guideline in map design (see figure 2). Now the perceptual or signifying properties of these visual variables have been reasoned out or tested (it is not quite clear what Bertin did to derive them) in a static situation, and it is not yet clear whether they affect one's perception in the same way when animated.

But in animation there are added variables that affect one's visual impression. These have been elaborated by DiBiase and MacEachren, and are supposed to be: display date (the moment the user views the scene), duration (the number of units of time a scene is displayed), frequency, sequence, rate of change and synchronisation. The way these dynamic visual variables affect one has hardly been systematically analyzed. A first result has been worked out by Yaman and Koop (1996), as can be seen in figure 3, and is elaborated upon further by Köbben in this volume.

Types of animated mapping

The basic principle of animation is to break down the continuous reality into a series of similar (while not completely identical) pictures (commonly known as frames) which, when viewed rapidly in succession, produce the illusion of motion (Koussoulakou 1990), as the eye-brain mechanism retains images for a short instant after the original objects have been removed.
One could ask why the current subdivisions discerned in literature should be adhered to. As it is, all of these seem based on production aspects, and one may ask oneself whether that is at all relevant to the issue. After all, it is the impression on the reader one should be concerned with primarily here, its connotation is secondary, and the way this impression is generated comes only afterwards (it will be discussed in the next section).
With Hayward (1984) one may discern between animated maps that show changes in shape, size, location, angle, colour hue, texture and structure, rate of change, scene, perspective and shot (zoom). A number of these types of change are visualized in figure 4

The situations these changes on animated maps refer to can be either two- or three-dimensional. Based on the work of DiBiase and others (1992), Dorling (1992) and Kraak (1994), both two- and three-dimensional animations can be subdivided into spatially dynamics and temporally dynamics, (see figure 5).

In temporally dynamic animations it is the map frame which is fixed and the action is within this map frame (Yaman and Koop 1996). A temporal brush can be used in these cases (see figure 5).

In spatially dynamic animations it is the action which is frozen, but the map frame is not (animating space can either be the process of panning and zooming into a large two-dimensional static image (Dorling 1992)), or the process of changing the representation mode of the action (Peterson 1993). Locations or attributes can be highlighted by letting them blink or having them displayed separately or consecutively. Changes in attribute can be realized for a confrontation through re-expression (reclassification or modifying the number of classes) of the same data. Analyzing the map through either geographic brushing, in relation to a scatter graph representation, or through scatterplot brushing also qualifies as animation because of its highly interactive character.
Maps can also be both spatially and temporally animated, when for instance during a historical process the viewer's standpoint is being changed, or the area rotated, etc.
All of these spatial and temporal animations can also occur in three-dimensional space instead of twodimensional space. For spatially dynamic animations this provides the added opportunity of producing fly-by's, walkthroughs and doing rotations.
Of course these two subdivisions (the one based on appearance and the one based on connotation) should be linked in some way, in the sense that rules should be worked out: as for instance when one wants to produce a temporal animation of a change in attribute, it is best to use changes in colour hue. How one then should go about to effectuate this comes under the heading of design and production.

Design and production of animated maps

In figure 7 yet another subdivision of animated maps is provided, now based on production methods. It is only at this stage that students will realize what a time consuming use of expensive software programmes is involved in the production of the cartographic animations, and how much schooling in sketching, modeling, painting, design story development, use of colour and lighting, shell scripting etc would have helped them.

The display of animations can be on-line or off-line, and in the first case this can be real-time (when the individual frames (either programmed or computed as inbetweens) are shown by the programme immediately after their computation) or real-time later (when the individual frames or inbetweens are being produced in batch mode and then moved to a file, to be displayed later. In off-line animation film or video techniques will be used for recording and play-off.
The production of computer animations departs either from the composition or from the improvisation mode. The latter is more used in video games and therefore disregarded here. The composition mode used a script according to which the individual frames are to be produced in a given sequence. Production can either be realised through computer-assisted drawing programmes, it can be completely through programming or it can be an algorithmic animation, in which programmes are used that can transform objects, let them move, etc. In cartographic education we will not go beyond the computer-assisted drawing programmes. These are either directed at producing individual frames one by one, or by drawing key frames and letting the programmes compute the intermediate frames (inbetweens). Keyframes is the name for the characteristic images that are decisive for the narrative.
At this stage, the course should provide some practical exercises with the more accessible of the special programmes that have been built to help computer animation. In Michael Peterson's new book (1995) there are many references to the relevant packages so there is no need to repeat them here.

Analysis of/use of/interaction with animated maps

The use aspect of animated maps is the one item that got the least attention in the growing literature on animated maps. The reasons stated why one should use animated maps are still scanty. Because they allow one to convey information quicker, because users might perform with them just a little better, or because users like them better than static maps - these are the reasons people have come up with until now.
When one devises tests to judge the effects of map animation, one has to ask oneself to what degree one's objectives in using maps have been adapted to their static properties. Now that maps have the potential of being animated one should perhaps revise these map use objectives.
The principal functions or objectives for static maps are:
So one should first ask whether these still also apply to animated maps, or whether animated maps would have new functions. The author cannot think of any, but he might be too much conditioned by static maps. Starting with the first function, navigation and orientation, here one decidedly will find directly one of the best reasons for producing animated maps: because it is much less expensive to produce convincing flight simulators than send pilots directly up in the air with a big Boeing. One might object by saying that in flight simulators pilots see the real landscape and not the map, but that is not true: they see a map all right which has been done up to look like the real landscape.
Back with one's feet on the ground, animation has something to offer as well. When setting a route on one's digital map, one can have the terrain displayed as seen from this route, showing where along the route one can be spotted by others from specific locations. It would allow one to spot landmarks along the route in advance, mark places where decisions should be taken, or caution should be exercised. So for this kind of objective animated maps would surely provide a different perspective. And one would be able to introduce the time factor as well, and make it a three dimensional spatio-temporal display, by letting the sun go down or even by changing the seasons.
The reference function is helped in animated maps by blinking and indeed is strengthened by the fact that the objects found can be queried as well. But that has nothing to do with animation. All the members of specific classes can be displayed and discerned separately; overview and detail can be integrated through zoom functions and generalisation thresholds.
Physical planning is about creating suitable environments for the future, taking account of the expected restrictions and conditions. To check whether the planned additions to or corrections of our ebvironments meet the expected results or standards set, one can exercise walkthrough programmes or, for larger objects, fly-by's.
In Education, the animation tools can be used for explaining both physical processes (erosion, sedimentation, the monsoon rains mechanism) and human ones (commuting, holiday patterns, distribution procedures, the build-up of population pressure or urbanization).
In management, which is more of an inventory-type of task, one may yet see little use for animation, but not so in monitoring. By playing sequences of past situations, one might be better prepared for trends that would not be spotted otherwise.
That would also apply to forecasts - here by playing the sequence of past images, one would be able to determine the rate of change, so that it would be justified to forecast when specific phenomena would reach a given location.
But this is all just conjunction - none of these animated map use situations have really been tested, with the exception of flight simulators, so that will be the main message in Teaching Animated Cartography: technically everything is possible, but cartographers should do research now, and analyse whether the animated cartographic products would improve on conveying the spatial relationships maps are about.

References

J.Bertin - Sémiologie graphique. Paris-Den Haag: Mouton 1967.
D. DiBiase, A.M.MacEachren, J.B.Krygier and C.Reeves - Animation and the role of map design in scientific visualization. Cartography and GIS, vol.19-4, 1992, pp 201-214.
D.Dorling - Stretching space and splicing time: from cartographic animation to interactive visualization. Cartography and GIS vol.19-4, 1992, pp 215-227.
S.Hayward - Computers for animation. Norwich UK: Page Bros Ltd 1984.
A.Koussoulakou - Computer-assisted cartography for monitoring spatio-temporal aspects of urban air pollution. PhD thesis, Delft: Delft University Press, 1990.
A.Koussoulakou and M-J.Kraak - Spatio-temporal maps and cartographic communication. The Cartographic Journal vol.29-2, 1992, pp 101-108.
M-J.Kraak - De rol van animaties in electronische atlassen. NVK Publicatiereeks no 12, 1994, pp 13-22.
M-J. Kraak and A.M.MacEachren - Visualization of spatial data's temporal component. in: T.C.Waugh and R.G.Healey (eds) - Advances in GIS research. Proceedings Spatial Data Handling. Edinburgh vol 1, 1994, pp 391-409.
A.M.MacEachren - Visualization in modern cartography. pp 1 - 13 in A.M.MacEachren and D.R.F.Taylor - Visualization in modern cartography. Oxford: Pergamon 1994.
S. McCloud - Understanding comics. 1993. Kitchensink Press, Northampton MA
M.P.Peterson - Interactive cartographic animation. Cartography and GIS vol.20-1, 1993, pp 40-44.
M.P.Peterson - Interactive and animated cartography. Englewood Cliffs NJ: Prentice Hall 1995
T.A.Slocum, S.H.Robeson and S.L.Egbert - Traditional versus sequenced choropleth maps: an experimental investigation. Cartographica vol 27-1, 1990, 67-88.
M.Yaman en R.O.Koop - Kartografische animatie in een theoretisch kader. Kartografisch Tijdschrift 1996 (forthcoming).