Abstract:

The growth of urban space occurs not only through urban land expansion, but also from the transition of urban functional land. The transition of urban functional land can profoundly reveal the internal features of horizontal expansion of urban space, and is the spatial reflection of urban functional agglomeration and diffusion. The paper takes the central city of Changchun as a case study. ArcGIS, AutoCAD and GIS analysis methods are used in the article. Based on remote sensing images, topographic maps and land use maps covering the years of 2003, 2007, 2010 and 2012, the study analyzes the external expansion and internal renewal of urban functional land. First, the paper analyzes the overall pattern of urban spatial expansion and the change of urban land structure. Second, the external expansion and internal renewal of urban functional land are used to express the transition of urban functional land. Finally, the paper explains the internal features of urban spatial expansion and urban functional agglomeration and diffusion. The goal of this work is to provide a new and effective way to study urban spatial expansion, enriching the theoretical foundation of urban space studies. The research reveals the following points: (1) Overall, a continuous urban sprawl is still the main mode of urban spatial expansion. (2) The direction of urban spatial expansion of Changchun has phased characteristics. (3) Residential land and industrial land are the major urban functional land types in Changchun. (4) Examining three study periods reveals that external expansion and internal renewal occur in different time intervals. (5) Internal renewal and external expansion of urban functional land are important indicators of urban spatial expansion.

Key words: urban spatial expansion, urban functional land, transition, internal renewal, external expansion, Changchun