Best practice guidelines for the design, production and presentation of vacuum formed tactile maps

Map size

The maximum size of a finished map will depend on the machine available for reproduction, and the type of plastic that is to be used. In the UK, ‘Braillon’ (PVC foil) is supplied by RNIB as sheets in three standard sizes, up to 280 x 290mm, which are only suitable for a braille reproduction machine (such as Clarke’s ‘Braille Reproduction 350’). Other sizes of PVC foil are available from a range of suppliers (see Appendix 2). These guidelines were drawn up from experience with a machine with a platen size of 432 x 228mm. Most maps were designed to A4 dimensions (296 x 210mm - A4 paper size is commonly used in UK) but some were designed to the full platen size. The size and shape of the site and the amount of detail to be included will probably dictate the choice of map size. Large sites may have to be represented on more than one map, in which case each section should have a strip along the adjoining edges that shows the same information as the contiguous map. Details of these overlapping segments should be explained in the ‘how to read’ information to ensure that the reader is able to relate one map to the next.

Once the maximum size has been decided, the actual size of the map will again depend on the size and shape of the site, the scale, and the way in which the map is likely to be used. A scale of 1:1,250 works well for maps of outdoor areas but may need to be adjusted. Map scale influences map size, information content, symbol size and spacing, and all the design elements may have to be ‘juggled’ to allow the creation of a product that fulfils the needs of its users. Scale may have to be distorted in some sections of a map to enable tactile discrimination between symbols [36], and therefore, the scale of a tactile map should be loosely interpreted [37].

Another word of warning! Draw the scale bar on a base map before either enlarging it or reducing it because the final version may not be easily calculable.