Bill - I believe if you dive into looking up "milksheds" you will likely find several pathways to help sort this out. From decades past, the regulatory issues of milk basis versus dairies, collection points, competitive marketplaces, distance to markets, and more have been studied by agricultural economists and rural development specialists many, many times. There are two methods: spatial linear programming and/or network/friction surface analysis. While not an expert, I believe the most effective LP's need inputs (coefficients) from travel friction studies? Same ideas hold for grain transportation and competing modes: trucks, rail, barges... versus terminals, engineered waterways/highways/rails, and market basis.
The LP stuff I will leave to you to dig into. Its history is quite deep given that the LP stuff was used to determine location of some our first interstate highways back East, in particular how they would interrelate to the "milksheds" surrounding New York, Boston and points between. The alternative would be the adjusting of several spatial analysis abstractions that Dr Berry has offered on his MapCalc related web pages: http://www.innovativegis.com/basis/Senarios/Default.html I believe friction surface as a proxy for speed and its travel complexity, start/go, uphill/downhill, combined with markets (ATMs in the example below) might be a conceptual start? Change the friction surface by changed assumptions and new flows occur. In this particular example, bank customers versus bank ATM locations, the friction surface is rather a simple one. And as they say time is money. Flows can be converted into cost/distance analysis. Net profits at end points can be guessitimated by margin analysis and simple assumptions on price elasticy? Travel-time and Customer Access http://www.innovativegis.com/basis/Senarios/TTime_scenario.htm Surface flows that conduit consumers to markets also have cost or friction surfaces. Pooling are essentially flows that can not achieve velocity. Mapping Surface Flows and Pooling http://www.innovativegis.com/basis/Senarios/Pooling_scenario.htm Dr Joe also has several books and in particular tutorials in the MapCalc Learner that will also illustrate other tricks to establish friction surfaces and impediments to natural flows... as the crow flies is not how you really get there... but if you build a bridge over a river, natural pathways change. Hope this might offer some insights. MidNight Mapper Aka neil -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bill Thoen Sent: Friday, September 22, 2006 3:53 AM To: MapInfo List Subject: [MI-L] Modelling Market Netowrks and Transportation Costs I'm interested in any good information on modelling markets and transportation costs. I think this a problem that can be solved using network functions, but I'd like to know more about the factors involved in such a problem. For example, suppose you had 100 cities that either bought or sold widgets and there were various transportation routes between the cities with some variable cost associated with moving the widgets. How would you go about designing a program that could tell you the current price of widgets in Gotham? If you added a new transprotation route betwen cities or increased the carrying capacity of one or more routes, how would that affect the price in Gotham then? Assume that there is a variable supply at the producing centers, and in some cases the can produce more than they can sell, while in other cases they can't produce enough to keep up with demand. I was thinking that it might be like water flowing into and out of a network of pipes. There are inflow and outflow points, there is pipeline capacity (that may or may not be maxed out), and I guess if you add reservoirs at various points in the network you would affect the response of the system to changes in demand. Anyway I'm just trying to get a grip on this sort of problem, so if anyone knows of examples or what parameters are involved, or even how to go about modeling such a process, I'd be interested in learning more. - Bill Thoen _______________________________________________ MapInfo-L mailing list [email protected] http://www.directionsmag.com/mailman/listinfo/mapinfo-l _______________________________________________ MapInfo-L mailing list [email protected] http://www.directionsmag.com/mailman/listinfo/mapinfo-l
