The existence of a center and periphery in any given human space and the study of the relations between them is a fundamental tier in geographic research. The spatial structure in various areas where groups of people dwell is not isomorphic; rather it is characterized by difference. This is expressed both in the physical domain and the different characteristics of human activity in the space, and as a result of this in the relations between man and his environment.
In the field of physical geography, the difference is expressed in diverse terrains: mountains, hills, coastal areas; in various kinds of climate; hot, cold, rainy, arid. This difference in various regions produces different forms of natural ground cover. In the field of human geography the difference is expressed in different patterns of activity. There are differences between urban and rural regions, between industrial and agricultural regions, between commercial and residential regions and between inhabited regions and regions that are unoccupied.
In general, it can be said that those places where favorable physical conditions exist – such as river valleys where there is an abundance of fertile land, in regions with a temperate climate or situated on a gulf or bay – are considered preferable for inhabitance by human society. An economy, social life, political life and cultural life can develop in these regions. In other words, extensive and intense human activity developed in these regions and therefore they were centers. On the other hand, in the regions whose natural characteristics were less attractive to human society – mountainous or desert regions and regions with extreme climatic conditions – if human activity developed there it was on a small scale. These regions were therefore considered peripheries. In the pre-modern periods the relations between the physical environment and human activity was of the utmost importance while in the modern era, innovative technology makes it possible to a certain extent to overcome natural conditions that are not favorable for the existence of a human society.
This description of the formation of center and peripheral regions is incomplete because there are numerous factors – economic, social, cultural and political – that are involved in defining a region as a “center” or as a “periphery”. Furthermore, under certain circumstances peripheral regions are of great importance, especially on a political and cultural level, and therefore will be considered frontier regions. Moreover, situations of center versus periphery can exist in different spatial significances, on the urban, the regional, the national and the global level.