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©Liddy Nevile



Charts, diagrams, tables


"The Oregon State University Science Access Project (SAP) has begun a series of projects intended to make it possible for authors of the future to present not just the pictures of information in electronic documents but also the original information from which those pictures are derived. That information could make possible good access by people with print disabilities. This paper discusses new developments for one important type of graphic presentation - the object-oriented representation.

The research is still far from complete, but some people, notably service providers for advanced students and professionals, may already find this a better and less time-consuming method for providing good access to a number of complex figures. One of the very great advantages to methods described here is that a figure can be made accessible for a broad population. A single labled web figure becomes accessible to people as diverse as braille- and non-braille reading blind people and people with severe visual dyslexia.

Current Techniques for Making Graphics Information Accessible

There are a number of audio technologies that are useful as substitutes or enhancements for visual presentation of maps, charts, diagrams, and other types of object-oriented graphical information. Many of these technologies rely on feedback from the computer to identify and display information about the important objects in the figure.

For example, [Jacobson and Kitchin] reported that blind people can "read" maps rather well by using a touch screen and running their fingers along a road or railroad track, interrogating cross streets as they are encountered, etc. This "map-reading" method requires not only a touch screen but also graphics software that can provide information to the viewer about any major object on the screen. In this case the names of streets, railroads, foot- and bike-paths, etc.

This access method relies on the user's ability to assimilate a mental spatial image of the map. A tactile image reduces the mental effort, and this combination of touch and audio(or braille) feedback has been found to be very successful in making maps and other graphics accessible to blind users. See [Parkes] reference.

Unfortunately, there are no technologies for displaying refreshable tactile images on-line, but it has recently become possible to create a tactile copy of a computer picture. This figure on a touch screen or other digitizing tablet permits a blind user to feel the tactile images, and receive audio feedback from the computer about those images. The [TIGER printer] is very convenient for this purpose, but people who have no TIGER can use [swell paper] to make tactile copies.

Off-line printing is time-consuming and makes it very difficult for a blind person to take advantage of features like zoom views. A number of on-line haptic technologies are being developed. The purpose of these devices is for use with virtual reality. One such technology, the haptic mouse, has already been introduced or announced for imminent release by several companies including Immersion Corporation (San Jose, CA, USA) and Control Advancements (Kitchener, Ontario, Canada). These devices may soon permit blind people to explore graphics on-line."

[TIGER printer] The TIGER TactIle Graphics EmbosseR was developed by the SAP and is commercially available from ViewPlus Technologies, Inc., 3223 NW McKinley Drive, Corvallis, OR 97330,

[swell paper] is a special paper that can be used to make tactile copies by radiant heating that causes black areas to swell.

At there are some examples of interactive data-driven graphics. At Corda offer software to produce Section 508 compliant accessible charts and graphing solutions:

PopChart Xpress:  A desktop application used to create accessible web-ready charts in minutes.  Copy data from a spreadsheet.  Best for charts with static data; and

PopChart [D]:  A server application for web sites that need a high number of charts and/or charts that access data in a database.

Haptic perception

'Haptic perception' is not the same but is equivalent to 'visual perception' for images. Those who see images learn to 'read' the images and their perspective. Cultural differences account for different ways of representing the third, and other, dimensions. For images in the western tradition, 'perspective points' determine the form of representation. For people who feel, rather than see 3D representations, - the objects get folded out eg a Coke can might have its flat side but also its two ends. For an interesting paper on this issue, see It points out that, for example, 3Dness is not represented in perspective, as for sighted people, but rather in relativity see images below:

two haptic versions of a table and accompanied by the following caption in the paper, "Fig. 4 Two equivalent solutions for flattening a long table. The upper one is chosen if the table is surrounded by other objects, the lower one if objects stand on the tabletop."





The Tiger Advantage Tactile Graphics Embosser is a Windows printer for blind people. Tiger was developed within the Oregon State University Science Access Project and is now commercially available from ViewPlus Technologies, Inc. Tiger is a tremendously useful tool for agencies that need to make graphical or highly structured information in tactile form. Standard (and reasonably user-friendly) Windows applications can be used to create tactile information or convert printed information to tactile form. One can, with help of sighted friends, create tables, graphs, bar charts, and other things from MS Excel, edit scanned images or imported clip art, and include them in text documents, and how to use a hot key plus Enter to convert text to Braille prior to printing on Tiger.


from about American Printing House for the Blind, 1839 Frankfort Avenue, Mailing Address: P.O. Box 6085, Louisville, Kentucky 40206-0085, Phone: 502-895-2405, Toll Free: 800-223-1839, Fax: 502-895-1509.

According to the advertising:

"Touch NOMAD Lightly: It Talks!

Put simply, NOMAD makes tactile pictures talk! NOMAD is a touch-sensitive pad on which raised-line graphics are placed. The NOMAD pad is connected to a personal computer (supplied by the user) and files describing the graphics are loaded. Once the appropriate file is selected, the user can touch various points on the graphic and NOMAD will describe them with synthetic speech.

Blind and visually impaired people can use NOMAD to independently learn about geography, geometry, biology, physics, physiology, electronics, astronomy, and any other subjects involving charts, graphs, diagrams or spatial concepts.

Some of the many uses of NOMAD include:

Use Ready-Made Graphics or Create Your Own

The makers of the NOMAD Pad refer clients to the American Print House (APH) or suggest they develop graphics themselves.

TouchBlaster Software Version 6.0 for the NOMAD Pad

"TouchBlaster(TM) Software Version 6.0 is now included with all new NOMAD pads. A few of the many new features of Version 6.0 include: digitized sound, a simplified menu option, a stand-alone mode that incorporates a built-in braille alphabet and four preset buttons, and much more! A Version 6.0 upgrade is available to users of previous software versions."

The National Centre for Tactile Diagrams

Based at the University of Hertfordshire UK, the Centre has good information including information about

Recording for the Blind & Dyslexic

from - - this group offer a big catalogue of ready-made diagrams


Tactile (haptic) devices

For information about tactile printing and overlays on graphics tablets and the editor for making SVG more hierarchically correct, see paper for CSUN at

There is a good description of the use of tactile presentation in "Audio and Haptic Access to Math and Science - Audio graphs, Triangle, the MathPlus Toolbox, and the Tiger printer", an IFIP98 paper.

Further information is available from an annotated list at

Last updated: 8 March 2002