Cities in the Sahara : spatial structure and generative processes
The present thesis examines some aspects of the structure of urban space found in particular towns in the Sahara, and the peculiarities in their dual organisation of the circulation systems: the streets and the roof terraces of the houses inter-connected by another system of walkways, which are exclusively reserved for the circulation of women across the settlements or parts of the settlements. The terrace morphology is developed in different forms and at various degrees of elaboration in these urban systems, which are usually seen as the result of some external determinant factor, such as religion, with the public being wholly male and women confined to the domestic sphere. Since there are no differences in religious terms between these systems, this view cannot be adopted to account for the pronounced differences in their spatial configurations. The study argues that: i- the terrace morphology is only one instance of the spatial mechanisms which enter in the separation and integration of the sexes, the global organisation of the street system is another; ii- these mechanisms, to include the terrace system, are intimately bound up with the nature of the urban fabric of these towns, which can be characterized as poorly connected and highly segregated, with a distinctive organisation of the main streets with regard to the settlement as a whole. The dense fabric of these towns with large urban blocks creates both, the high level of segregation of the street system and larger roof surfaces; iii- both, the nature of the urban fabric and the global organisation of these systems are strongly related to the generative processes of urban formation, and the underlying rules followed in the aggregation of buildings on the ground. These rules are seen as expressions to social restrictions on relations between and within male and female groups. The computer simulations of the urban growth show that the highly segregated nature of the spatial fabric and its distinctive global organisation are the by-product of a more localized process of building aggregation. The study concludes that the dualistic structure of these towns and its variation lies in the greater emphasis on male-female relations and the greater localization in the structuring of space. It demonstrates then that the relation between the terrace morphology and the urban form of these towns is shown to exist at the deepest level of space organisation, at the level of the generative rules of settlement formation. By this, the study uses an architectural approach to broach the question of relationship between the social and spatial aspects of these towns.