Identification and analysis of urban fabric considering external space: Taking Shanghai as an example

Urban fabric preservation is a crucial objective in urban conservation. Identifying fabric types is essential for protecting and maintaining urban fabric. However, precise methods for identifying fabric types are lacking. This study expands the concept of fabric from the similarity of individual buildings to the similarity of buildings and the external spaces between them, as well as from a two-dimensional relationship to a three-dimensional perspective. A K-means clustering method, which uses building footprint area, building height, and exterior building space area as primary indicators, is proposed for urban fabric identification. The manifestation patterns of urban fabric in various areas of Shanghai are examined as a case study. Results shows: first, the identification method proposed in this study has a good identification effect, with an identification rate of 77%. Second, four types of urban fabrics constitute the main urban fabric of Shanghai. Third, the implementation of policies such as the delineation of historic and culture areas has played a certain role in the protection of historical fabric, but the historical fabric of unprotected areas is disappearing rapidly, better conservation policies are urgently needed. This study develops fabric identification method and analyses the fabric of Shanghai’s urban area, providing valuable insights for research in urban morphology theories and methods, as well as urban preservation and revitalisation practices.