Tactile maps for blinds [1]

To guarantee the independence of visual handicapped people and to improve their ability to manage the challenges of everyday life, it is essential to provide tools representing information about space. Tactile maps and reliefs are ideal for making mental maps of the reality which are so basic 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 18^th century. After the brilliant creation of a simple and reasoned tactile type by the 16 years 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, so they need not really modelling terrain. But if the representation of a whole region is needed, also 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 and writings can intersect each other, without becoming illegible. Braille can not be varied that way. Thus, in tactile maps abbreviations were used to save space. This requires an explication in a legend or in a supplement volume. 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 Atlantes have been made.

To facilitate map reading of tactile map for people with little remaining visual abilities, such products often are 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 this techniques function in practice.

Single-line streets

Elevated streets

Two lines marking the roadsides

Lowered streets

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