Tactile maps for the blind [1]

Tactile map of south america
Tactile map of South America,
Sonnenberg, school for visually handicapped children and adolescents, Baar

To guarantee the independence of visually handicapped people and to improve their ability to manage the challenges of everyday life, it is essential to provide tools representing spatial information. Tactile maps and reliefs are ideal for forming the mental maps of reality, which are so essential for navigation. They allow studying them calmly. Using the sense of touch, a person needs much more time to explore a map than using eyes, because it is necessary to study each part of an object separately and then piece the parts together to comprehend it in its entirety [2].

The first tactual maps have been created in France in the 18th century. After the brilliant creation of a simple and reasoned tactile type by the 16 year old Louis Braille, the teaching of blind children in special institutions increased and so did the need for adequate teaching aids.

Often, tactile maps are used for city maps and maps of buildings, thus they do not really need to model terrain. However, if the representation of a whole region is needed, terrain has to be modelled. In both cases, the products are three-dimensional.

One speciality concerns the inscriptions. In visual maps, inscriptions can be manipulated in many ways, such as font, size, width, direction. Furthermore, writings can intersect each other without becoming illegible. Braille cannot be varied that way. Thus, in tactile maps abbreviations are used to save space. This requires an explication in a legend or in a supplement. Because of the limited sense of touch, a tactile map contains much less information on the same area than a graphical map, and the amount of signatures is strongly limited. To provide more information, the technique of overlays is often used: Several maps are made of the same area and in the same scale, but with different content. If too much elements are placed on a tactile map, the user becomes confused. In this manner, whole atlases have been made.

To facilitate the reading of tactile maps for people with little remaining visual abilities, such products are often coloured and inscribed with black conventional types.

There are many different ways and techniques to create tactile maps:

For the representation of streets, three versions are in use. A signature of a street can consist of two thin elevated lines marking the roadsides, a street can be an elevated line in comparison to the houses, or it can be lowered. All these techniques work in practice.

Example of single-line streets
Example of elevated streets
Single-line streets
Elevated streets
Example of two lines marking the roadsides
Example of lowered streets
Two lines marking
the roadsides
Lowered streets
Pictures from Podschadli p.36-39.

One important requirement for teaching materials for the blind is the need for one single copy for each pupil, since only one person at a time can touch an object. Furthermore the extent is limited. It should be possible to embrace the whole map with both hands, since the relative position of the two hands is crucial to gather the correct image. For these reasons, moulded plastic maps are ideal. They are lightweight and durable, and it is possible to produce them fast and easily.

Tactile relief of the canton Zug
Tactile relief of the canton Zug (Switzerland),
Sonnenberg, school for visually handicapped childs and adolescents, Baar

[1] This part mainly bases on the articles of Edwin Podschadli.

[2] Liner, Devon Skeele. Tactile Maps. 1987. p.iv.