where wj is the weight (say, population or traffic generation capacity) assigned to the jth city. Solution of the location problem for single or multiple junctions then becomes a special example of the plant location problem, which may be approached by the Kuhn-Kuenne numerical approximation method described in Section 5.6.1. Note that solution for large networks demands multiple iterations based on alternative trial' locations for the junctions, and that the best of these is used to approximate the optimal configuration
(c) Alternative definitions of distance. The shift in location shown in Figure 3.7A assumes that the only relevant item in determining the network configuration is that of movement costs weighted distance in equation and building costs are ignored. If the network were very expensive to build, then.we would expect equation (3.2) to remain the relevant criterion to keep mileage, and therefore construction low as possible costs, as This dilemma in defining exactly what we minimum distance is mean by illustrated by Figure 3.8. In this diagram, six line networks have been drawn, each of which provides a different answer to the problem of building a route network linking five cities. The first network (Figure 3.8A) shows the minimum