“Planning is an intellectual process with aspects of different and changing importance.” That is also why applications of planning and its interpretation differ.
In particular, we want to emphasize: The nature of planning can be characterized as the deliberate and active creation of ideas that are conceived to realize specific aims and already contain deliberate judgements.
There are two more conditions to be fulfilled, if planning should be effective in reality:
Planning is constrained by existing resources, otherwise it would become utopian.
Plans have to be finished (or cancelled) at some point in time, otherwise they would become useless.
The intended purpose of planning is clear:
Planning, meaning the deliberate, active creation of ideas (involving certain goals and judgements, subject to constraints set by time and resources), always aims at “optimizing future activities”. (1)
(1) Marquardt, K., Aufgaben ökologisch fundierter Landschaftsgestaltung, in: http://www.iwoe.de/Welcomeseite.html, "Planungsgrundlagen", "Enzyklopädie der Landschaftsgestaltung"