This research investigates representation techniques for spatial and related information in the design of tactile displays for pedestrian navigation systems. The paper reports on a user survey that identified and categorized landmarks used in pedestrian navigation in the urban context. The results show commonalities of landmark use in urban spaces worldwide. The survey results were then used in an experimental study that compared two tactile techniques for landmark representation using one or two actuators. Techniques were compared on 4 measures: distinguishability, learnability, memorability, and user preferences. Results from the lab-based evaluation showed that users performed equally well using either technique to represent just landmarks alone. However, when landmark representations were presented together with directional signals, performance with the one-actuator technique was significantly reduced while performance with the two-actuator approach remained unchanged. The results of this ongoing research programme can be used to help guide design for presenting key landmark information on wearable tactile displays.
TopUser Survey Of Landmark Use
Several researchers, May et al. (2003), Burnett et al. (2001), Raubal and Winter (2002), and Klippel and Winter (2005), have suggested that a navigation system’s value could be improved by providing landmark information in addition to the common use of directional information, however, there has been no reported use of landmark information in tactile navigation displays.
Landmarks for human navigation can be any objects or places that are stationary, distinct and salient (May et al., 2003; Grabler et al., 2008). Landmarks are identified by their salience (Raubal & Winter, 2002; Klippel & Winter 2005), subjectively and depending on the mode of navigation (Allen, 1999). That is, landmarks are not objective and universal but are chosen subjectively by individuals, particularly in learning and recalling turning points along routes (Sorrows & Hirtle, 1999).
Landmarks play two major roles in navigation: as an organizing concept for space and as a navigation tool (Golledge, 1999). In organizing space, landmarks can represent a cluster of objects at a higher level of abstraction or scale and present an anchor for understanding local spatial relations (Golledge, 1999). For example, symbolic landmarks, such as the Eiffel Tower in Paris or the Statue of Liberty in New York, can come to represent an entire city. They serve as reference points; other landmarks or objects are recalled as being near them and not vice versa. These symbolic landmarks are defined by their visibility from a distance and, especially, their great cultural importance (Sorrows & Hirtle, 1999).
As a navigation tool, landmarks are used to identify decision, origin and destination points. They also provide confirmation of route progress and orientation cues for homing vectors (Golledge, 1999). Landmarks enable the human to construct spatial relationships between objects and routes for the development of her cognitive map of the space (Raubal & Winter, 2002; Millonig & Schechtner, 2005; Michon & Denis, 2001).
According to Allen (1999), human wayfinding can be categorized into three types: traveling to a familiar destination (commuting); traveling to an unknown destination (questing); and exploring the area, which may or may not involve visiting important landmarks (exploring).