The flow of information within a national territory creates the conditions which favour increasingly intensive interaction between different areas, manifested in the movement of goods and services between them. The intensity of this interaction and the volume and diversity of the goods and services which interchange, thus become a measure not only of national integration but also of the level of development within the country. The bases of this interactive exchange of goods and services derive from regional variations in ecological conditions and natural resource endowments, uneven distribution of productive factors and their indivisibility, as well as regional variations in human resources, traditions, taste and consumption patterns. 1