Interactive sonification for blind people exploration of geo-referenced data: Comparison between a keyboard-exploration and a haptic-exploration interfaces

Representing geographical information in non-visual modalities is a complex problem that deserves special attention since this could be a way to facilitate the access of visual impaired subjects to this type of special information once proved the correspondence among the different sensory representation. Tactile maps and, more recently, on-screen text readers have sought to solve this problem but tactile maps are difficult and expensive to produce and text readers do not allow an analogical representation of information. Recently alternative solutions have been found by using sonification (the use of nonspeech audio to convey information). iSonic, a prototype developed by the H.C.I Lab. at the University of Maryland brings a new interactive approach allowing users to navigate into acoustic sonificated maps. In iSonic each subject action on the map triggers sounds that inform about the placement and the features of a given region. This sonification design allows two different kinds of map exploration: one using the computer keyboard (KB), the other one using a touch tablet (TT). KB exploration proceeds by discrete steps. Subjects can move through the map using the arrow keys. KB exploration is analytical, systematic, and symbolic. Differently, TT exploration allows users to move freely in every direction with no constraints. TT exploration is global, analogical, and leads to a more isomorphic representation of the map space. Our research aimed at: • Evaluating how well iSonic unable users to perceive and represent shapes and data patterns on maps. • Assessing the effects of exploration methods (KBTT) on map knowledge acquisition and pattern recognition.