A photograph is not the same as its subject, and it is not sufficient to reconstruct the subject, but it's still a representation of the subject. Even a few sketched lines are something we recognise as a representation of a physical object.

I think it's fair to call one process that can imitate a more complex one a representation of that process. Especially when in the very next sentence he describes it as a "projection", which has the mathematical sense of a representation that loses some dimensions.