Comparative Study On The Built Environment Evolution Of Nanjing Old Town Fringe

After experiencing rapid urbanization development,large cities in China generally face problems such as rising land development costs,slowing incremental land development,limited construction land supply and mismatch of urban space demand,which restrict a new round of urban development.China’s urban development has entered the middle and later stage of urbanization,characterized by high-quality development and structural adjustment of both increment and inventory,and urban development is undergoing a transformation process from outward expansion to old town fringe and inward optimization and filling.In this context,the city has transformed from a single center to a multi-center system,and the mezzanine zone between the old city and other peripheral functional groups has also ushered in an opportunity to transform the old town fringe from the edge zone to the urban center.Therefore,it is of great significance to quantitatively grasp the spatial evolution characteristics of the old town fringe.Based on the built environment index evaluation system,this study enriched the research system of the old town fringe area from the perspective of the built environment,and carried out a comparative study of its spatial evolution characteristics from a dynamic perspective.This study made up for the blank of the tracking research and renewal of the old town fringe area,and supplemented the urban renewal theory.The first part(Chapter 1,Chapter 2)is the introduction and related research review.The background,purpose,significance,method and innovation of this research are expounded.This paper reviews and summarizes urban renewal theory,built environment theory,spatial evolution theory and fringe area theory,which lays a theoretical foundation for the follow-up research and the construction of comprehensive cognition.The second part(Chapter 3)is the case study,the index system and the research method framework.Taking Nanjing and its old town fringe area as the research object,the index evaluation system and spatial clustering method suitable for this study were constructed by referring to the existing research index system of built environment.The third part(Chapter 4)is the study on the spatial evolution of the built environment of the old town fringe.From the "Density","Diversity","Design","Destination accessibility" and " Destination to transport" of the five first-class index system and 20 categories of sub-index system research and interpretation.The characteristics of its spatial evolution are proposedThe fourth part(Chapter 5)is the spatial evolution clustering and characteristic analysis of the old town fringe.Through the combination of K-means clustering method and Arc GIS grouping classification method,the spatial evolution of the old town fringe area is grouped into five categories: "stable promotion type","transformation core type"," property-oriented type","micro-renovation type" and "demolition vacant type".Secondly,the paper explains the spatial distribution,spatial pattern and land use change of the old town fringe.Then,the driving factors of its spatial evolution were explored based on the empirical study.Finally,the spatial optimization measures of the old town fringe were eliminated based on the analysis.The fifth part(chapter six)is the conclusion discussion.Summarize the research results and innovation points.