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Design considerations for haptic and auditory map interfaces.

Article Excerpt
Communicating Spatial Information to the Blind

Two major obstacles that blind and visually impaired individuals face in becoming fully functioning members of our modern society are access to print media and the ability to freely move throughout modern environments (Golledge 2001). Much of the information we use in modern society is available either exclusively in print form (most newspapers, books, and magazines), or through mediums that are largely visual-centric such as television and movies. Blind and visually impaired individuals must either find an adaptive technology to overcome these print and movement barriers, or face exclusion from full participation in society. The goal of our research is to develop effective methods for communicating spatial information to blind and sight-impaired individuals through maps and graphics utilizing haptic and auditory cues. Haptic feedback (delivered as a stimulus through the skin and aided by kinesthetic perception of the position and movement of the joints and muscles) and auditory feedback allow blind and visually impaired users to gain some of the same information normally presented through the visual sense. Our research combines a program of experimental research and human subjects testing with the development of cartographic interfaces that use auditory and haptic cues. Over the course of this research effort, many details have emerged about the capabilities and limitations of communicating spatial information through haptic and auditory interfaces, and will be communicated here.

A preliminary goal of this paper is to briefly review tactile map research and means of presenting spatial information to the blind and visually-impaired. With this review as a foundation, we present our Haptic Soundscapes research, which builds on the concepts of tactile mapping and extends them through the use of auditory and haptic devices that can deliver cues and communicate spatial information to the blind and visually impaired. Our Haptic Soundscapes research introduction will include a brief introduction, a discussion of our work with designed experiments and user feedback, followed by a technical description of how we design and construct Haptic Soundscapes maps. Ultimately, we hope that this paper can stimulate thought and discussion, as well as enrich the background of cartographers who are interested in developing maps for the blind and visually-impaired.

The Internet is an excellent information dissemination medium, particularly for individuals who are mobility impaired and must plan travel carefully. Maps and graphics of streets, highways, shopping centers, urban areas, and public facilities abound. However, very few of these maps and graphics are of any use to the blind and visually impaired. Although technology for accessing text information from web pages is maturing, technology for non-visually accessing raster and vector graphics is still in its infancy. The research presented in this document and the wider body of literature by other key researchers in this field will enable future maps and graphics to be produced in formats that can be interpreted and used by blind and sight-impaired individuals. The goal of increased accessibility for maps and graphics echoes the goals of the new computing movement (Shneiderman 2002), which seeks to foster computing technology that is "in harmony with users' needs" and "support[s] relationships and activities that enrich the users' experience" (ibid., 2).

Tactile Maps

Tactile maps have been used for several decades to communicate simple spatial information to the blind and visually impaired. Although they are not common, they can be found in some public libraries and in some large public facilities, where they are displayed on a wall or in a kiosk, generally as raised lines in top of a visual map of the facility. Tactile maps are generally of two distinct types: vacuum formed maps made of heat-softened polyvinyl chloride (PVC) sheets that are vacuum formed over a mold producing raised areas, and microcapsule paper maps that are formed by printing a black and white graphic onto special capsule paper which is differentially heated, causing the dark areas to expand upwards.

The International Cartographic Association's (ICA) Commission on Maps and Graphics for the Blind and Partially Sighted has explored both tactile map technologies, reviewing the relative advantages and disadvantages of each (Perkins 2001). In summary, there is no clear preference of one technology over the other, but each technology has its own advantages. Vacuum formed maps can be mass produced in a consistent manner and have a wider ranging capacity for symbolization, but a significant investment in equipment and training is required in order to produce the master mold for the map and to operate the machinery. Microcapsule maps can be created using a photocopier and a uniform heat source. They are cheaper and easier to produce but lack the range of symbolization that can be incorporated into vacuum formed maps. One significant drawback to both vacuum formed and microcapsule maps is portability and dissemination. Tactile maps, because of their very nature, cannot be folded without introducing some unwanted tactile features into the surface of the map. Because they must be stored flat and unfolded, they are difficult to transport, particularly when they are large. To overcome this problem, Repro-Tronics, Inc. (http://www.repro-tronics.com/) has produced a cloth-based bumpy capsule paper which is not affected by folding.

Taylor (2001) provides some insight into the problems and challenges of tactile map production. He describes an involved educational effort to train tactile map specialists from several countries and his subsequent problems in deploying the equipment necessary for these individuals to contribute cartographic material to a tactile atlas. Although the most difficult issues were bureaucratic in nature, it is clear from his presentation that large tactile map production projects are very difficult in terms of technology, administration, training, and implementation.

A fertile area for tactile map research has been experimentation with symbolization and development of standardized symbols. Tatham (2001) suggests the goal of creating a standard method for tactile map symbolization is unsustainable, due to the wide variation in the use and perceived meaning of tactile symbols. A sighted map user's training in visual...

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