Academic journal article Human Factors

Navigational Checking Using 3D Maps: The Influence of Elevation Angle, Azimuth, and Foreshortening

Academic journal article Human Factors

Navigational Checking Using 3D Maps: The Influence of Elevation Angle, Azimuth, and Foreshortening

Article excerpt


To aid orientation, navigators utilize maps. Determining geographical location therefore requires the navigator to compare map features with land features. To determine congruency, the navigator first perceives and then processes features in both the map and the world until a decision of match or mismatch is made.

An aviator's task of continually comparing map features with features in the forward field of view (FFOV) will be referred to as navigational checking. Although this task seems simple, the navigational checking process using standard 2D paper maps breaks down quite often, even during visual meteorological conditions (Antunano, Mohler, & Gosbee, 1989). Upgrading to expensive continuously updated three-dimensional (3D) maps is feasible, but would this reduce navigational checking errors? The spectrum of available map formats is broad, but their associated effects on this psychological comparison process are undetermined.

During navigational checking, perception and processing of the map and FFOV continue until enough evidence is accumulated (e.g., Fitts, 1966; Pachella, 1974) and a match/mismatch decision can be reached. Given the wide array of available map formats, the speed and accuracy of the match/mismatch navigational checking decision is largely influenced by various psychological factors that the map format might impose, such as availability of features, display resolution, cognitive transformations, prior knowledge, expectancies, and so forth. The psychological processes used during navigational checking and the relevant literature are briefly summarized next.

Fundamentally, navigational checking requires some information to be available in both the map and the FFOV. However, many map formats inherently make some features unavailable for comparison with the FFOV. For example, additional heading or route information overlaid on a display could clutter critical features necessary for comparison. Similarly, maps seldom contain cultural features such as buildings. In such instances some potentially relevant information never reaches the pilot because it is not available, and it subsequently cannot be perceived or processed for the comparison, thereby possibly increasing the difficulty of navigational checking.

Other map formats degrade the perceptual quality of features that are available. Reducing resolution makes available map objects perceptually more difficult to decipher, spatial distances harder to resolve, or both. Prior research has shown that human performance deficits are associated with poor contrast sensitivity (Shinar & Gilead, 1987), "jitter" or vibration (McClumpha & Selcon, 1989), and low pixel resolution (Bennett, Winterstein, & Kent, 1967; Cuqlock-Knopp & Whitaker, 1993; Kibbe & Stiff, 1993), whereas aids such as camera filters can benefit performance by increasing resolution (Johnston, 1968).

Certainly, availability and resolution of objects are not the sole determinants of navigational checking performance; cognitive transformations substantially influence both perception and the ultimate match/mismatch judgment. When a map is simplified (e.g., road maps do not depict buildings), the pilot might fill in objects or extrapolate existing contour lines in order to more precisely make a confirmation. Conversely, highly detailed or cluttered maps might bring about an "attentional filtering" transformation (Eley, 1991; Schmidt & Kysor, 1987). Other cognitive transformations might also exist that are necessary to bring the map and FFOV into congruence, such as integration, mental rotation, "zooming," or "envisioning" (Aretz & Wickens, 1992; Eley, 1988, 1991; Wickens, Liang, Prevett, & Olmos, 1994). Finally, top-down processes such as prior expectations, strategies, speed/accuracy trade-offs, or schemas might strongly influence the outcome of a navigational checking decision.


A search of the literature revealed few studies analogous to navigational checking. …

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