I was associated in such works a long time back.
In fact some of the Real Estate Consultancies ( almost all of them Multinationals) in India do this study regularly to assess the changing potential vis-a-vis the market prices of built space.
Mostly used for commercial areas for two reason:
1. The private sector companies do this to assess the existing situation by finding out the total builtup space available and the total space sold out and being used.
(a) Done by a physical survey, this would give the real picture of the demand,
need and the supply of space.
(b) A temporal study and that too if done on maps( A GIS would be great to use
if the data is available, would bring out the changing trends and directions of
growth.
(c) Many times the results are startling about the kind of space which may be
lying waste. Sometimes the built up area figures may not match with the
parking and traffic figures.
(d) Such studies are also done by the real estate people for assessing the markets and suggesting to their clients. The government planning agencies to see if there is any glut in the market and use that data for new development
strategies or redevelopment plans.
2. Market studies for new development are done by large coporates in locating their whole sale and retail commercial activities. Some large township developers have also started doing some analysis of the housing stock and related retail commercial before they embark on to the construction stage.
Although I still advise some companies on how to go about such studies, most of my approach is based on ground realities and information available to me due to my professional experience and being a local lad I have the pulse of the market. Generally it doesn't go wrong.
SInce I haven't come across a specific methodology which can be applied anywhere when it comes to market analysis, I can only suggest that you work out your own methodlogy which would include secindary data collection, interaction with the building approval agencies, interviews and questionnaires, physical recce and photographs if possible, data collection on the spot posing as a customer ;-).
I would be interested to see your reply and if you are developing any methodology and what the results are.
All the best to you.