31 Land Use patterns along the Nile
LAND USE PATTERNS ALONG THE NILE
Spatial relationships among phenomena on the earth’s surface are a concern of the geographer. Explanations of these relationships are sought by examining all aspects of spatial phenomena, and when it becomes apparent through repetitive observation that certain processes have causal effects on spatial relationships theories are formulated for universal application. The basis of geographic inquiry is location. The use of location theory other than to explain landscape patterns enables planners to determine the effects brought about by the changes they would introduce. The knowledge of the forces influencing existing landscape patterns also provides planners with a basis for adapting their schemes to the landscape.
One of the most noted of location theories is the Von Thünen land use model, or “concentric rings” theory (Figure 1). In 1803 Johann Heinrich von Thünen devised a model predicting land uses around the market centre. In this model he hypothesized that land use will change as a function of distance from the centre. This is explained in terms of transportation costs. Priority of land use will go to the activity yielding the highest net return per unit area of land. The net return or economic rent is then determined by variable operating costs, the most significant being transportation to and from the market. A product difficult to transport can only be economically feasible when grown near the market and when demand is high enough to justify it. Each location with respect to the market has a set of cost variables which in turn determine the land use bringing. the highest economic rent.
Products of demand which are bulky, perishable and otherwise difficult to transport are cultivated near the market so as to reduce transportation costs. Those products which are more easily shipped are produced further from the market unless the demand for them is exceptionally high. The resulting land use pattern is a function of transportation costs, and with distance from the market the products of the land use will bear decreasing costs of transport per unit.
Several assumptions are made to clarify the model. First, there must exist an economically isolated and homogeneous agricultural region which consists of one market town. All production is sold and all consumer items are supplied in this town. It must also be assumed that all of the people of the community have freedom of choice and behave in order to maximize profits. Transportation methods and soil fertility are assumed to be the same throughout the region. Von Thünen conceived of this idea in the context of early nineteenth century Germany when transportation was by horse cart and the most difficult products to be shipped to the market were vegetables, fruit, dairy products and firewood. The production of these constituted the land uses nearest the market. Further away, the land use decreased in intensity of cultivation as fallow