1. Dimension of Representations

This category relates to the format of the representation and its purposes in relation to audience.

a) Mode
This relates to whether the representation is an image, video, simulation or interactive. This is flexible as more categories can be added; for example, image can be a drawing, diagram, photograph etc.

b) Aesthetic
This relates to how aesthetic elements and decisions have been implemented in the representation. The aesthetic also relates to the aesthetic experiences a reader of the representation may have. This is not only in the “eye of the beholder”, but rather specific features also associated with visual design principles.

c) Disciplinary
This relates to whether the goal of the representation is disciplinary or not. For example, it uses representation conventions accepted in disciplinary community.

d) Pedagogical
This relates to whether the goal of the representation is to teach concepts to various levels. Pedagogical representations are designed specifically for pedagogical purposes as a variation on the full disciplinary representation. They do not always require disciplinary knowledge, and often the requirement is at a lower level than that of a disciplinary representation. This sub-category describes the particular features that are different to or allow for the unpacking of the full disciplinary representation features with a pedagogical aim.

2. Features of Representations

This category relates to components the constitute a representation. Representations can be composites made up of various semiotic systems and resources.

a) Use of images
This relates to whether the representation uses imagery; for example, photographs of galaxies.

b) Use of diagrams
This relates to whether the representation incorporates diagrams as part of the composition.

c) Use of symbols/icon
This relates to whether the representation uses symbols and icons. These could be pedagogical or disciplinary.

d) Use of text to annotate/explain
This relates to whether the representation uses text to communicate hidden information in the representation; or to clarify the information presented in the representation.

e) Use of mathematical notation/equations
This relates to whether the representation uses mathematical symbolism to help communicate information that would not be possible via text. These can be at different levels of complexity/sophistication depending on intended audience.

f) Use of data (directly/indirectly)
This relates to whether the representation uses data, whether it is directly in the form of a graph; or indirectly of an image based on data; for example, the Cosmic Microwave Background Map.

3. Translation of Representations

This category relates to how representations change or are repurposed for a particular context.

a) Simplification
This relates to how the representation has been changed to change the affordances. This change could be from the full disciplinary representation to make it accessible at a particular level. This can either by via the addition or removal of elements/semiotic resources.

b) Combination
This relates to how the representation uses a combination of one or more separate representations.

c) Analogies
This relates to the representation of analogies for pedagogical purposes. Analogies can be simplifications. However, simplifications can happen without analogies, for example, taking a graph and removing the disciplinary aspects.

4. Interrogation of Representations

This category relates to a deeper exploration of representations, which include the aims and the meanings they encompass for various audiences.

a) Appresentation
This relates to the hidden information that the representation contains but is not made explicit. Often appresented information is only accessible at a high degree of disciplinary discernment.

b) Disciplinary Affordances
This relates to the degree of disciplinary information that is contained in the representation. It is directly related to the concept that the representation frames and enables.

c) Pedagogical Affordances
This relates to the degree of pedagogical scaffolds that are contained in the representation. In essence, how the representation scaffolds conceptual understanding for the students. It also depends to some extent on how the educator presents the representation to the student.