Documentary-Based Urban Digital Twins and the Historic Urban Landscape Approach: Parametric and Geospatial Modeling for Sustainable Urban Regeneration and Cultural Heritage Conservation

Historic urban landscapes are at continuous risk of loss due to urban modernization and the demolition of built heritage. Scan-based documentation methods such as laser scanning and photogrammetry become inapplicable, leaving demolished sites undocumented and unrecoverable through existing digital heritage workflows. This study develops a documentary-based Urban Digital Twin (UDT) framework for reconstructing demolished historic urban landscapes through the integration of historical documentation, geospatial analysis, and parametric modeling within the Historic Urban Landscape (HUL) approach. As a feasibility study, the framework reconstructs Chahar-Bagh Bala Street in Isfahan, Iran, a four-century-old promenade among the oldest urban streets in the Middle East, whose royal garden entrances, towers, water features, and promenade have been almost entirely replaced by industrial and modern structures. The methodology applies a nine-step workflow, integrating georeferencing, viewpoint reconstruction, cross-source validation, and HBIM parametric modeling, using historical maps, travel account engravings, archival photographs, and measured plans. The reconstruction confirms the historical existence and spatial locations, established through convergent visual evidence, of two lost royal garden entrances. The study further quantifies long-term historic green infrastructure loss, finding that approximately 70% of the original garden cover has been replaced. This replicable framework supports evidence-based heritage governance and sustainable urban regeneration, including the reintegration of historic green infrastructure into contemporary urban planning, particularly for rapidly transforming cities of the Global South.