Urban morphogenesis and fractal pattern: scaling invariance of traditional Islamic cities in Algeria

Abstract

Understanding a form requires knowledge of its process of emergence and its mechanisms of development, in other words, its morphogenesis. Similarly, urban morphogenesis remains a central question in urban studies. Using quantitative methodologies from complexity theories, this research explores aspects of the urban morphogenesis of the traditional Islamic city, which has long remained enigmatic. This study examines the fractal model hypothesis applied to the traditional Algerian Islamic cities of Algiers, Tlemcen, Ghardaia and Ouargla, using network theory. Specifically, the methodology focuses on ‘betweenness centrality’ and ‘closeness centrality’ applied to the street networks of these cities as a primary manifestation of urban structure. This experimentation verifies the scale invariance property of the street networks. We investigate the correlation between betweenness centrality and closeness centrality, influenced by street distributions, and assess their conformity to power-law distributions. The analysis of power-law distributions confirms the scale invariance property of these cities. Integrating network theory and fractal model, this approach provides novel insights into the formation and evolution of traditional Islamic urban environments.