From Open Geographical Data to Tangible Maps: Improving the Accessibility of Maps for Visually Impaired People

Visual maps must be transcribed into (interactive) raised-line maps to be accessible for visually impaired people. However, these tactile maps suffer from several shortcomings: they are long and expensive to produce, they cannot display a large amount of information, and they are not dynamically modifiable. A number of methods have been developed to automate the production of raised-line maps, but there is not yet any tactile map editor on the market. Tangible interactions proved to be an efficient way to help a visually impaired user manipulate spatial representations. Contrary to raised-line maps, tangible maps can be autonomously constructed and edited. In this paper, we present the scenarios and the main expected contributions of the AccessiMap project, which is based on the availability of many sources of open spatial data: 1/ facilitating the production of interactive tactile maps with the development of an open-source web-based editor; 2/ investigating the use of tangible interfaces for the autonomous construction and exploration of a map by a visually impaired user. 1. “VIZUALISATION” OF SPATIAL INFORMATION BY VISUALLY IMPAIRED USERS Online maps have become widely used by sighted users, but they are not accessible to visually impaired users. The most accessible maps are tactile maps with outlines printed in relief. Those maps are called raised-line maps and provide visually impaired users with tactile cues that help to understand geographical data. In educational centers for blind and visually impaired people raised-line maps are commonly used during geography, mathematics, physics, etc., lessons, as well as during orientation & mobility sessions. These maps are either embossed in a plastic sheet or printed on a special heat-sensitive paper that makes the ink swell when it is heated. Designing a tactile map is a complex and time-consuming process that requires tactile graphics specialists called transcribers. According to the Braille Authority of North Canada, the transcriber must first select the information that will be presented on the tactile map, and possibly simplify or reorganize it so that the original map information may be spread over several tactile maps. Each element of the original map needs to be categorized into one of the four primary components (area, line, point or label) and will be transcribed with a specific outline or texture. The resulting graphic generally consists in one title, a north indicator, and the tactile map upon which Braille abbreviations are displayed. The Braille legend is usually presented on a separate sheet as illustrated in Figure 1. Several studies have shown that visually impaired people could benefit from tactile maps. For example, Jacobson (1992) found that tactile maps provide visually impaired adults with a mental representation of the area that is represented. Espinosa et al. (1998) corroborated these results by demonstrating that visually 1 http://www.brailleauthority.org/tg/web-manual/index.html impaired participants who learned a route from a tactile map performed as well as visually impaired participants who learned the same route from direct experience, i.e. by walking it. However due to the lack of commercialized tactile maps it is difficult for the visually impaired to access spatial data (geography, geometry, technical drawings, etc.) and spatialized data (demographics, economics, etc.) but also to travel autonomously, which is likely to affect their personal and professional lives (Passini et al., 1988). Figure 1. Example of a tactile map used by a visually impaired user during a geography lesson. The planisphere is simplified and presented on a sheet of paper. The legend is presented on a