moreminent-minimization models: statement 201
development represents only one extreme case in a set of problems in which areas are grouped as near as possible to a point or line. Ring development is discussed in the following section because it is graphically simple and clearly linked to the urban hierarchy, not because it is unique or exclusive. To understand ring formation, let us consider the simple case of a land-use area to be placed as near as possible to a single point; then a circular form, commis paribus, is the minimum-movement solution from all parts of thee= to the point. Clearly, in this elementary case, the relationship between cl.„ and A is simply da„ — "Alit. This trivial problem becomes considerably more interesting as we differentiate alternative land use areas (A" A1, A,J associated with I, 2, ..., n different land-usc types.
Table 6.3 Derivation and movement inputs'