Inherited spatial configurations and emerging real estate logics: An analysis of vertical densification trajectories in the pericentral area of Blida, Algeria

This article investigates the trajectories of vertical densification in the colonial pericentral area of Blida (Algeria), focusing on the relationship between inherited spatial configurations, planning regulations, and emerging real estate dynamics. The study is based on an original database of building and demolition permits issued between 2019 and 2024, combined with diachronic mapping of high-rise buildings (HRBs) constructed between 2012 and 2024 using a GeoEye-1 orthoimage (2012) and orthorectified Google Earth imagery (2019 and 2024). The methodological framework integrates urban morphological analysis, spatial statistics, and space syntax indicators to examine how street-network configuration and plot structure influence redevelopment opportunities. Results show that vertical densification occurs primarily through an incremental demolition-reconstruction process driven by private investment rather than coordinated public planning strategies. Redevelopment is concentrated in the most accessible and spatially integrated pericentral areas, where parcel size, plot configuration, and network connectivity provide favorable conditions for investment. Initially, HRBs are strongly aligned with historically integrated radial corridors, reflecting path-dependent development shaped by the inherited urban structure. Over time, however, verticalization progressively expands into adjacent and less integrated neighborhoods, revealing a gradual spatial diffusion of redevelopment. Overall, the findings indicate a transition from outward urban expansion to an urban renewal model based on parcel-by-parcel replacement of existing buildings. The study demonstrates the persistent influence of inherited spatial morphology on contemporary redevelopment patterns and contributes to broader debates on the spatial determinants of urban densification in postcolonial cities.