Planning seems to have been on a journey to find itself within the academic and societal structures within our society from when we've starred to develop plans for our town and cities. I had been the domain of other professions like Architecture, Engineering and even an Administrative arm of some councils, but planning has been able to establish itself as a credible science on itself.
As far as I'm aware, the above is all Planning, but not even planning or financial planning. Just like the medical field has doctors and philosophical doctors, the establishment and promotion of the notion of a doctor means something also scientific but you would never call a person who works in planning as a doctor (unless you've done a doctorate).
So what is Planning?
Planning is Simcity, obviously! You just click on the areas that are residential, commercial and Industrial, and it's done... NOT! Planning is a broad area and field. It encompasses not only development assessment of housing but it includes transport planning, forward planning, master planning, developing regional plans, federal plans for the country. Planning, is mainly an issue of governance. Planning is not Architecture, Landscape Architecture, Engineering nor is it Urban Design. It is not involved with the intricacies of design details, but the policy implementation of those themes.
Planning is Social Engineering
So in one way you can say it is Social Engineering as it determines appropriate uses an are to it's best potential in a non biased way. This is where conflicts between locals and planning policy come to a head. Some planning schemes have been stated to of being in effect that even a nuclear power station if it complies to all of it's conditions can be built within a residential area. This in my opinion is where planning fails. Where policy and common sense leave a gap so that a development can become political and be pushed around within the public realm despite the financial funding of private enterprise is stifled and restricted.
Planning & Politics
Planning, as it affects people and their livelihoods becomes in its nature, political. We are after all, political when it comes to things that affect our worlds. If a development goes ahead and casts shadows and creates noise along your boundary, of couse you are going to be upset. If it can be proven that these things are not going to impede on your livelihood, then realistically, the development by all rights should go ahead, if those criteria are criteria that can be established as conditional. That might sounds jargony, but in reality this is how planning is achieved.