In the book Design Elements by Timothy Samara, Mr. Samara depicts a spectrum for the representation of images, ranging from pictorial (literal/concrete) representation to non pictorial (abstract) representation. Both these territories contain sub territories, denoting/describing the "mode" of representation. Please note image below.
In the scale it is observed that the representation of images (In this example a sign depicting an "eye") falling within the category of "pictorial" can be identified as literal portrayals of objects that exist in reality. ie. They resemble objects that exist in the real world.
Those identified as "pictorial" representations include the sub territories of Literal, Concrete and Iconic. As shown in the image below. It can be clearly observed that the representation of images within the "pictorial" sub territories can all represent objects that can be identified in the real world, with varying level of detail (either expansive or reductive in detail)
Conversely on the opposite end of the spectrum, of "Non pictorial" representation, ie. the objects depicted do not resemble anything that exist in physical reality, the following sub territories are defined: Diagrammatic, Connotative and Symbolic. As shown in the picture below.
Within the sub territory labelled as "Diagrammatic" While representing the signified ("An eye"), The syntax of the form used appears to depart from what could be described as "existing in reality", but still relates to some extent to a literal representation of an "eye", albeit using a reductive and abstracted syntax. Within the context of the pictorial representations of the eye, the connection can be made.
Within the sub territory labelled as "Connotative" it is not clear what is being said or represented. Being non pictorial the representation should not match anything that exists in reality and With the term "connotative", it would imply the signified (in this case the eye, or parts of it) should not be directly referenced. But from what I am interpreting from the imagery shown above the "connotative" label, it does seem to represent objects found in reality, and it does seem to literally reference the eye. In the first example The imagery appears to be a zoomed in iris and pupil with eyelashes albeit somewhat stylized and mediated, and in the second example, concentric lines are drawn that could represent an iris. So in both examples I can see that the signified "the eye" (or parts of the eye) is directly being portrayed and literally being referenced.
Within the sub territory labelled as "Symbolic", The symbol of a letter "e" is represented. It does not exist in reality, but it is a culturally learned symbol that represents a character of the English language. The same can be said about the symbol for a power button. It has no meaning until it was culturally learned to have a meaning. By reading about semiotics, It is my understanding a sign that is "Symbolic" could also be represented by objects that exist in reality. Example an image of a dove could be symbolic for peace. This would not match the definition of "Non pictorial" since a dove does exist in reality.
I have some confusion regarding regarding the non pictorial(using only abstract forms): diagrammatic, connotative and symbolic representations. What is the difference between each ? Using the same signified idea, How would each be distinctly visually represented, in terms of both subject matter and visual syntax.