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Article Excerpt
Introduction
"The primary motivation in new technology is often novelty" (Goodchild 1988, p. 317).
In their look at animated maps, Campbell and Egbert (1990) caution that too often, animated map sequences seem constructed more for their novelty than for their usefulness. Computer-generated, three-dimensional fly-over animations were first produced in the 1980s to showcase the legitimate computing prowess of leading research laboratories such as NASA's Jet Propulsion Laboratory (the creators of the very popular LA: The Movie in 1987). In the last decade, these maps became increasingly common with the development of affordable software (to create them) and the Web (to distribute and view them). Numerous Web sites (e.g., PBS), museums (e.g., The Smithsonian), and television programs (e.g., running/cycling coverage from the Olympics) utilize fly-over maps to bring a "high-tech feel" to the traditional overview/reference map (Figure 1). With the release of free 3-D geospatial rendering engines, notably Google Earth and NASA Whirlwind, a new era of user-controlled fly-over maps seems to have arrived. However, it is our belief that most fly-over maps proceed too quickly. They are also easily forgotten and provide too few useable thematic or reference cues. This results in disorientation, which ultimately begs the question: what can be done to improve fly-over maps? This research seeks to answer that question.
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The goal of this research is not to discredit flyover maps or suggest they should not be used but, rather, to identify and validate cartographic techniques that can make them more effective, and to encourage those who make such maps to think about how specific map-reading tasks can be supported through the informed use of embedded orientation/location/landmark aids.
Like any kind of map, fly-over maps are made for many reasons. In surveying common practices in the design of fly-over maps, Harrower and Sheesley (2005) found that the most common uses are to:
* Engender a sense of place (e.g., tourism);
* Present locational or spatial information (e.g., where something is, how high it is);
* Serve as a 3-D topographic map (often using traditional 2-D topographic maps draped over DEMs);
* Serve as pre-visualizations (e.g., visual impact of a new highway); and
* Show the results of simulation and modeling (such as output from a climate model).
For some of these uses maintaining correct orientation and spatial awareness is not necessarily critical, and in fact, "getting lost" may be part of the intended experience. However, when fly-over maps are expected to perform as overview/reference maps and communicate positional or locational data, they often fail miserably, as has been shown repeatedly in user testing (Darken and Sibert 1996a; Elvins 1997; Vinson 1999; Chittaro and Burigat 2004; Bowman et al. 2005). Although these researchers have documented how easily people can become disoriented in immersive three-dimensional worlds, they have also shown that simple (and sometimes quite elegant) enhancements to these worlds can greatly reduce disorientation and improve user navigation. For example, Fuhrmann and MacEachren (2001) and Fuhrmann (2003) demonstrate how augmenting the three-dimensional oblique egocentric perspective--known as "first-person perspective" in electronic gaming--with a second 2-D locator map can greatly improve users' performance with immersive maps (improving both orientation and navigation skills). Rice (1999) found that orientation problems in fly-overs may be alleviated with the use of verbal narration; maps enhanced with a narrator identifying important features in the landscape and providing verbal direction cues.
Building on these successes, this paper reports on human subjects research that evaluated the effectiveness of four kinds of visually embedded orientation aids that were designed to improve spatial awareness and reduce disorientation within fly-over maps (Figure 2). Our basic hypothesis is that all of these orientation cues should improve both directional awareness (what direction are you facing?) and recall/drawing of the path traveled. More specifically, we hypothesize that the compass orientation cue will greatly improve directional awareness, and the monorail will be most helpful in recall (and drawing) of the path traveled.
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The Need for this Work
Apart from the research mentioned above, very little user-testing research has been done within GIScience on fly-over maps, and few design guidelines exist that explain how and when to best use them. For example, we know little about the perceptual and cognitive impact of frame rate, viewing angle, flight length or speed, flight-path complexity versus scene complexity, or variable versus static flight height. Students wishing to make 3-D fly-over maps today have few places to turn for guidance in how to make these kind of maps, and for what kinds of map-reading tasks they are especially well suited (and just as importantly, not suited). It appears today's technology is ahead of cartographic theory that could guide its use.
Taking a step back from fly-over maps, this lack of formal cartographic guidance is all the more obvious given that three of the largest players in mapping today have each invested heavily in 3-D mapping technology (Google Earth, Microsoft's Virtual Earth 3D, and ESRI's ArcGIS Explorer). It is worth noting that these 3-D Web-based mapping services are aimed at non-expert users, part of the larger democratization of cartography (Morrison 1997; Rod et al. 2001; Krygier and Wood 2005). Fortunately, researchers outside GIScience have been investigating these issues, and it is this literature we draw on here. In fact, user orientation and navigation were identified as major research challenges by funding agencies on both sides of the Atlantic. An influential special report of the Joint European Commission/National Science Foundation (see Brown et al. 1999) outlines fundamental challenges in constructing and using immersive and virtual environments (VEs).
The original motivation for this research came from semester after semester of showing fly-over animations to students in cartography classes: few of the students could agree on what they just saw or, more importantly, transfer the just-witnessed oblique map perspective to a simple flight path on a two-dimensional map. Many were unsure of how much territory was traversed, how many times their compass direction changed, the...
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