"diagram"

means a diagram which has been signed by a person recognised by law as a land surveyor, and which has been approved or certified by a surveyor-general or other officer empowered under any law so to approve or certify a diagram and includes a diagram or a copy thereof prepared in a surveyor-general's office and approved or certified as aforesaid, or a diagram which has at any time prior to the commencement of this Act been accepted for registration in a deeds registry or surveyor-general's office;