Improving the design of tactile maps

What is it about?

People with visual impairments (PVI) also use maps – they are called tactile maps and are usually composed of both: tactile content for the blind and strongly simplified graphic content for the visually impaired users. Since the resolution of a finger, which is most commonly used by PVI to explore tactile maps, is much lower than this of an eye, sings on such maps and blank spaces between them must be much bigger. Besides, due to characteristics of tactile perception, i.e. reading maps fragment by fragment rather than perceiving a whole map sheet at once, tactile maps must be compact enough to be covered by arms span of a seated user. All the above makes designing legible and cartographically sound tactile maps complicated and expensive. It is hard to fit all of these enlarged sings on such a small map sheet and still maintain its legibility. One of the ideas to simplify this process that we wanted to verify, was to apply height differentiation of tactile signs to improve their discrimination and thanks to that, reduce the required horizontal distances between them. By doing that we could either reduce the dimensions of the final tactile maps sheets - thus reducing their production cost, or put additional signs on the same map sheet without losing legibility. As it turned out, our hypothesis was right. We have confirmed in a controlled study session with 30 blind and visually impaired participants that variating height of tactile signs facilitates perception of their content.

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Photo by David Martin on Unsplash

Photo by David Martin on Unsplash