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Joshua A. Miele, Ph.D.
The Smith Kettlewell Eye Research Institute
2318 Fillmore St.
San Francisco, CA 94115
The goal of Smith-Kettlewell's Tactile Map Automated Production (TMAP) Project is to develop a web-based software tool for rapid production of highly specific, tactile street maps of any location in the USA. Until now tactile maps have been difficult and expensive to obtain or produce. Local street maps for any specific town or city have been almost impossible to obtain in an accessible format. TMAP brings together existing geographical information system (GIS) resources with currently available computer-controlled embossing and engraving technologies to yield a revolutionary tool which will significantly impact education, orientation, and mobility of blind and visually impaired travelers. The users of the TMAP service will be able to utilize a web or telephone interface to specify the location and size of the desired tactile map. The map file and related key information will be generated immediately and sent via download or postal mail to the user. Maps will be highly customizable to the needs and desires of the user. For example, map labeling may be in Braille or raised print, specific paths of travel or locations of important facilities such as train stations may be indicated, etc. Because clutter is such a critical factor in the readability of tactile maps, TMAP algorithms display only the features relevant at the selected scale. For example, only major streets are shown if a map of a large area is to be produced.
In addition to its anticipated practical benefits, the TMAP project may also be of use as a research tool. Many wayfinding and cognitive psychology studies have investigated the degree to which blind and visually impaired people are able to integrate spatial information obtained from tactile maps. With the TMAP project researchers will, for the first time, have a virtually unlimited set of customizable tactile maps available to use in their research.
The Underlying Technology
Geographical information such as the location of roads, buildings, train stations, parks, etc., is stored in a database called a geographical information system (GIS). The TMAP project is currently working with a free GIS available from the US Census Bureau called the Topologically Integrated Geographical Encoding and Reference System (TIGER). This GIS provides relatively complete and accurate location information for roads and many other features in the United States and its territories. In the future, it is possible that other GISs will be used in TMAP, however, the TIGER line maps currently provide an excellent level of functionality at an extremely reasonable price.
The prototype of TMAP and its features is being developed in a computational and modeling environment called MATLAB (a product of The Mathworks, Inc.). In an earlier project, The Smith-Kettlewell Eye Research Institute's Rehabilitation Engineering Research Center (SKERI-RERC) developed a set of software tools for producing tactile graphics from within MATLAB. These tools are now being used to produce tactile maps. MATLAB also includes a pre-existing set of software tools for manipulating maps and GIS data. Furthermore, MATLAB includes a set of features that allow easy data exchange with a web server. Taken together, these features provide all the functionality necessary to implement the TMAP via a web interface.
The TIGER data is primarily concerned with infrastructural features such as roads and buildings, although some hydrological features are included. While the primary concern of the TMAP project is with road and street information, topographical information is also of interest. High resolution elevation data is available from the United States Geological Survey (USGS) in the form of digital elevation models (DEMs). Using a computer-controlled milling machine it is possible to produce highly accurate, 3-d models of terrain features such as mountains, valleys, lakes, and rivers. Like the TIGER data, these DEMs are available free of charge and downloadable from government web sites. Again, MATLAB can be used to control the production of the 3-D models from the DEM data.
The User Interface
One of the goals of the TMAP project is that the maps be accessible to as many people as possible. This means that good design of the user interface is critically important to the success of the project. There will be two means of interacting with the TMAP engine: 1) a simple text-based web interface suitable for use with a screen reader, and 2) a telephone interface requiring no computer or embosser.
The TMAP server will keep track of a certain set of basic preferences for each user. These include the type of embosser or tactile output system the user has, what type of labeling the user prefers (Braille, raised print, etc.), and what types of geographical features the user tends to request. Users will be able to specify the mapping area in several ways. Local street maps can be specified by providing a point location (such as an intersection or street address) together with a dimension of the map to be produced (five blocks square, half a mile, etc.). Alternatively, a local street map can be specified by providing two or more locations to be included on the map. This second method will be of particular use in planning pedestrian routes.
Users may wish to produce maps of entire cities or regions. Depending on the desired resolution of the maps, this may require the map to be divided into several sub-maps. In cases such as this, one or more master maps will provide a general overview of the entire area at a relatively large scale. The master maps represent the entire area of interest including large features such as major roads and highways, along with indicators for the specific area displayed on each of the finer-scaled sub-maps.
The major difference between the web- and telephone-based interfaces is that the latter will not allow the downloading and production of the requested map. The intended user of the telephone interface is someone who does not use a computer, and who may not own a Braille embosser or other tactile output system. Such users may not be comfortable with computer technology, but may nevertheless desire access to and benefit from tactile street maps. In such cases, and in the case of web users who do not own an embosser or other tactile output system, the maps can be produced by a third party and sent via postal mail. Indeed, some users who own embossers may wish to take advantage of this feature in situations where a third party production facility may be able to produce higher resolution or larger format tactile maps. This would be particularly true of the 3-D models produced from the digital elevation data -- very few individuals possess either a CNC milling machine or the skill to use it.
Who Will Benefit from TMAP?
Generally speaking, almost all blind and visually impaired people who are able to feel tactile diagrams can potentially benefit from this technology. It offers the possibility of high-quality street maps of any location in the US. People who make use of these maps will be able to learn more about the road and street configuration around their homes, schools, and places of work. This knowledge has the potential to enhance their ability to independently navigate their local environment, thus facilitating use of local entertainment, employment and educational opportunities.
In addition, teachers of orientation and mobility skills will be able to provide their students with high-quality tactile maps depicting locations of interest. Many teachers of O&M already use tactile maps in this way, but TMAP will allow them to produce them more quickly and easily than ever before. In addition, many O&M instructors who may have previously avoided using tactile diagrams in their lessons, may now find them more convenient to incorporate, thereby improving their effectiveness.
Public and private entities, such as museums and hotels, often provide patrons with maps depicting the local geography. Such facilities will now be able to use TMAP to provide blind and visually impaired visitors with this same information in an accessible form. TMAP will therefore provide businesses and other organizations with an easy means of providing map information in an alternative format, thereby assisting them to comply with relevant accessibility legislation.
Although none of the components of TMAP are in themselves revolutionary, the combination of these existing technologies offers an opportunity for something that has never before existed: the availability of tactile street maps of any location at any scale. With the wide-spread availability of high-quality, inexpensive tactile maps, blind and visually impaired people will finally have unrestricted access to geographical information of a kind that has never before been possible.
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