Projection Vs Realisation

Projection is a logical relation between the material order of experience and the semiotic order of experience — between a macrophenomenon (a senser sensing or a sayer saying) and a metaphenomenon (an idea or locution).

Realisation is both a logical relation and an experiential relation.  

As a logical relation, it is elaboration, a type of expansion.  

As an experiential relation, it is one of symbolic identity, a type of identifying relation.  

Realisation is an ideational relation between different levels of symbolic abstraction.

"Reading Images"

		Token	Process	Value
consciousness (Symboliser symbolic processing)	projects	meaning x construed by language (Value)	means	y
		pictorial re-presentation of visual experience (Token)

Why Stratify The Content Plane?

Halliday & Matthiessen (1999: 237):

Of course, what we are recognising here as two distinct constructions, the semantic and the grammatical, never had or could have had any existence the one prior to the other; they are our analytic representation of the overall semioticising of experience — how experience is construed into meaning. If the congruent form had been the only form of construal, we would probably not have needed to think of semantics and grammar as two separate strata: they would be merely two facets of the content plane, interpreted on the one hand as function and on the other as form.