The post-1945 period has demonstrated significant shifts in spatial and urban systems. Although settlement patterns have always been in a state of flux, contemporary changes in cities and in urban systems show transitions which have profound consequences for the spatial organisation of our world. These changes concern both the internal mechanism of the urban system and the position of the city in a total spatial system (see Gauthier 1970; van der Knaap 1980; Korcelli 1980). It should be noted, however, that the urbanisation trend has not demonstrated a uniform pattern within and between nations.