the problem is that i have several hundred Sow farms (supply sites) that all ready exist and over 400 Nursery Farms (demand sites) that all ready exist. i need to assign nursery farms to the sow farms based on network impedance (road length or travel time) and supply and demand.
You can use Location-Allocation but it does not solve the capaciated problem. So you can create a location-allocation layer, load your Sow sites as facilities with a Facility Type of "Required" and then load your nursery farms as Demand, set the properties of the LA layer to solve for the number of Sow sites you loaded and solve. The demand will be allocated to the nearest Sow site.
However if you want to solve the capacitated Allocation problem, i.e. all facilities are fixed and ahve a supply that cannot be exceeded, then use an ArcScript that uses the Network Analyst to compute the network distances between your supply and demand locations and then uses a linear programming package to solve the problem. You can get that ArcScript here:
Thanks Jay! I all ready have downloaded the script and have used it. I was hoping that the new ESRI Location Allocation would be able to solve the same problem. Does ESRI plan to develop uch a tool in the future?