The definitions according to Togaf ;
– Baseline : “A specification that has been formally reviewed and agreed upon, that thereafter serves as the basis for further development or change and that can be changed only through formal change control procedures or a type of procedure such as configuration management.”
– Target Architecture : “The description of a future state of the architecture being developed for an organization. There may be several future states developed as a roadmap to show the evolution of the architecture to a target state.”
– Gap : “A statement of difference between two states. Used in the context of gap analysis, where the difference between the Baseline and Target Architecture is identified.”
– Transition Architecture : “A formal description of one state of the architecture at an architecturally significant point in time. One or more Transition Architectures may be used to describe the progression in time from the Baseline to the Target Architecture.”
So to translate this to the terms that are already being used in “the real world” too;
– Baseline : The baseline is the “AS IS” situation. This is something you should already be aware of, as this is your operational baseline for your configuration management, and thus the basis for all change requests (as probably generated from an architecture change).
– Target : This is the “TO BE” situation, your “flag in the distance” to indicate where you want to be.
– Transition Architecture : These are your waypoints to get to your goal (being the target). Sometimes these are called “Interim Targets”, where they are called “Plateau” according to the “Implementation & Migration” extension of Archimate.
– Gap : The “diff” between your starting point (“AS IS”) and your destination (“TO BE”).