It occurs to me that I have never addressed the issue on this blog.
Basically, maps online are not accessible. According to Treasury Board, this is because the image of the map needs a longdesc attached to it in order to meaningfully describe the map. This can easily be found right at the beginning under checkpoint 1.1 in the W3C Web Content Accessibility Guidelines:
- 1.1 Provide a text equivalent for every non-text element (e.g., via “alt”, “longdesc”, or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ascii art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video. [Priority 1]
- For example, in HTML:
- Use “alt” for the IMG, INPUT, and APPLET elements, or provide a text equivalent in the content of the OBJECT and APPLET elements.
- For complex content (e.g., a chart) where the “alt” text does not provide a complete text equivalent, provide an additional description using, for example, “longdesc” with IMG or FRAME, a link inside an OBJECT element, or a description link.
- For image maps, either use the “alt” attribute with AREA, or use the MAP element with A elements (and other text) as content.
The creation of a map requires a multitude of data, raw data that the viewer never sees, only in its graphical form. How do we turn that raw data into a meaningful text description, as well as include information that we automatically infer when viewing the map? The data behind interactive maps is constantly changing as you pan, zoom, turn on/off layers etc, the text description will need to be dynamic in order to address this.
ajfowler 
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January 12, 2009 at 1:55 pm
jon
I’m still stuck on the question of scope. My first inclination is to try to narrow down the problem by getting you to declare a small set of map attributes that you want to provide accessibly for. This small set of map attributes could include some fuzzy things like “locality” (i.e. the fact that from a map you can compare distances between points, easily), and less fuzzy things like recorded VOx levels. But with those in hand you could start thinking about how to best represent them accessibly (longdesc or otherwise). At the moment the problem just seems, um, unbounded.
January 17, 2009 at 1:29 pm
The Third Bit » Blog Archive » Graduate Students
[…] Alecia Fowler wants to make map data accessible. […]
January 20, 2009 at 4:23 pm
James Coughlan
You may be interested in Josh Miele’s Tactile Map Automated Production (TMAP) project: Using GIS Data to Automatically Generate Raised-Line Street Maps (for blind and visually impaired users).
TMAP “was initiated in 2003 by Dr. Joshua A. Miele with the goal of developing the first web-based software tool for rapid production of highly specific, tactile street maps of any location in the USA. Before TMAP, tactile maps were difficult and expensive to obtain or produce, and tactile street maps for any specific town or city were almost unheard of. TMAP brings together existing geographical information system (GIS) resources with currently available computer-controlled embossing technologies to yield a revolutionary tool with significant implications for education, orientation, and mobility of blind and visually impaired travelers.”
http://www.ski.org/Rehab/TMAP/