Hi Georgia Braille,
TG Guidelines 1.3 states, "No diagram should be routinely omitted if a viable method can be found to render it tactually comprehensible. On the other hand, diagrams that do not add additional, necessary information than what is stated in the surrounding text may be omitted. Sometimes ..."
The intent of the TG Guidelines writers was to communicate that graphics should not be automatically dismissed in print to braille transcriptions. The diagram you provided in the attachment is a good example of exactly WHEN to include a graphic. This diagram should be included even though the text seems to explain the process for computation and define/describe the concept being taught. In the print text, the student is provided the explanation and a diagram to illustrate the concept. The braille reader should have the opportunity to read the text and see a diagram to illustrate the concept as well. Learning is accomplished through a variety of media (auditory & tactually). Equal access to materials can only be accomplished when the information is provided in a variety of formats.
Let me know if you have any other examples you'd like me to review for inclusion...Diane