Here is a quote from Amanda Cox (http://eyeofestival.com/speaker/amanda-cox/):
"The annotation layer is the most important thing we do... otherwise it's a case of here it is, you go figure it out."
Our next layer is one that can often be neglected. However, as this quote suggests, annotating visualization is such an important features of our design. It is about taking care of your audience, recognizing who they are, what they might know already, and what they don't know.
Done well, annotation can help explain and facilitate the viewing and interpretive experience. It is the challenge of creating a layer of user assistance and user insight: how can you maximize the clarity and value of engaging with this visualization design?
As discussed ...