High-Quality text descriptions of visual elements in online interactive versions of traditional print mechanical engineering textbooks
Even before the Covid-19 pandemic, there was an increased utilization of online course materials. Circumstances created by the pandemic increased the need for high quality online course content. These online course materials should comply with accessibility regulations and guidelines to provide an equal learning experience for all students. Although these guidelines describe broad requirements, specific standards for creating text descriptions of visual elements, both static and interactive, have yet to be created for mechanical engineering content. Research is lacking regarding accessibility of images and other visuals within online interactive mechanical engineering texts. Defining standards for how engineering visual elements like images and animations are textually described will provide a baseline to measure the effectiveness of visual elements for students who require assistive technology, such as screen readers.
The goal of this paper is to define accessibility standards developed for textually describing images, figures, graphs, animations, and other visual elements for a series of online interactive mechanical engineering textbooks (zyVersions) that have been adapted from traditional print textbooks. The group of content authors working on these zyVersions have written text descriptions (alt text) for the visual interactive content (animations) that have been added to the traditional textbook and in many cases have added to the text descriptions for figures including images, equations, and graphs that already appeared in the print text. The standards that have been used by this team of content authors include: (1) Writing text that balances precision with conciseness; (2) Structuring alt text to first capture important information, then incrementally filling in finer details; (3) Well-defined procedures for describing certain types of visual elements, such as phase diagrams and phase transformation plots in materials science and engineering, T-s, h-s, and P-v diagrams in thermodynamics, output response plots in control systems, as well as other common visual elements in mechanical engineering courses; and (4) Writing text for animated visual elements that describe in detail all dynamic processes and movements in the animation. This paper describes our guidelines in detail, and presents examples from three different zyVersions used in mechanical engineering courses. These standards can be modified for use across various engineering disciplines and will enable authors of online content to provide higher quality material that meets accessibility standards.