Spatiotemporal Changes And Expansion Modes Of Construction Land In Hangzhou City Based On Historical Maps And Remote Sensing Images

At present,a lot of research on urban expansion in a relatively short time scale have been done based on remote sensing image analysis,and some theoretical models or hypotheses of urban expansion have been proposed,such as the “diffusion-coalescence” hypothesis and the growth type theory.However,due to the time limit of remote sensing images,there is still a lack of research on spatiotemporal changes of urban expansion and its theoretical applicability on a longer time scale.Based on the historical maps and remote sensing images of 9 periods in Hangzhou from1914 to 2018,construction land data was extracted through visually interpreting digital historical maps,and classifying CORONA,Landsat TM and OLI images using object-oriented method.Spatiotemporal changes and expansion modes of construction land have been analyzed based on these data.The magnitude change of construction land were described by expansion speed and expansion intensity indicators.Markov-ANN-CA model was used to simulate the urban expansion in two continuous development periods: 1914-1937 and 1992-present.The "diffusioncoalesce” hypothesis and the growth type theory have been tested using landscape pattern analysis,and the study area was analyzed in three spatial scopes: whole research area,inner zone and outer zone,which were devided based on fractal theory.The results showed that:(1)Contruction land in Hangzhou showed expansion trends in1914-1937,1949-1966,and 1978-present,but almost stagnated in 1937-1949 and 1966-1977.(2)Based on the simulation data based on Markov-ANN-CA model,keeping the development trend in 1912-1937 may has adverse impact on urban expansion;construction land has expanded rapidly since 1992,and will be further concentrated in the future.(3)Based on landscape metrics analysis,the inner zone of Hangzhou showed “diffusion-coalesce” cyclical change in the past hundred years,which can support the “diffusion-coalesce” hypothesis;(4)Inner zone has showed a significant alternation of three growth types;however,edge-expansion has been dominant in the whole research area and outer zone,which needs to be further judged on its role in the process of urban expanison.(5)The research methods based on fractal theory to explore the differences in each urban spatial scopes helps better understand the urban expansion modes.The integrated analysis based on historical maps and remote sensing provides a path for long-term urban research.