If you have an image on a Web page, it’s recommended that you include an ALT tag for screen readers, but what if your image is a complex concept map?
But you don’t always have to hide the long description from the sighted. A principle of Universal Design is to include the benefits of accessibility for everyone. You can have perfect vision, but still not understand the diagram, so why not include a description that everyone can access?
One example I did was for a portfolio concept map. I have a typical concept map/site architecture diagram, but I also rendered it as a text outline which may be more usable by a writer used to outlines as well as to the visually impaired. Another benefit was that I could convert the text to links pointing to more information. While I could have added hot spot links to the diagram, but then I would have had to accessify that as well and considered usability. Text is so mercifully quick and cheap. All I had to add to the image was an ALT tag saying that the image matches the text outline.
The thing I like about the Universal Design concept is that I feel that my “accommodations” really can work for everyone. I’m happy to implement technology for someone using a screen reader, but it’s even more satisfying to add accommodations that benefit multiple audiences. Everyone is included that way in one audience.
Update Another Unhidden Long Desc
Another time I had to generate a long description was to describe the history of modern English dialects . This time the description is in the “Text Version” section. An additional reason NOT to hide a long description is that it could benefit whoever doesn’t understand the diagram. That is, there may be sighted people not entirely comfortable with diagrams would prefer to see the information described as text.