ABSTRACT
At regional scale, populations have 'activity loci', such as river valleys or plains, within which social and economic interchanges are relatively rapid. In the ancient world, for instance, Mesopotamia, the Nile Valley, and the mountain-rimmed coastal plains of Greece, gave rise to distinct societies with a high degree of internal communication. Within these, there was often a close relationship between particular activities and certain land units, such as agriculture on alluvial areas, pasture on hills, markets at crossroads or bridging points, harbours in sheltered coves with relatively deep water inshore, and irrigation systems in arid areas starting at the debouchment of upland watercourses on to plains. The use of aerial photographs helps unravel the resulting palimpsest of tectonism, erosion, deposition, and changing human settlement patterns, which make up local history.
