基于历史光栅数据的城市空间形态演变及影响机制研究

Research on Urban Spatial Form Evolution and Influence Mechanism Based on Historical Raster Data

本文研究以美国谷歌公司Google Earth软件提供的1978年—2018年的长沙市行政区域内年度卫星历史光栅影像为基础,利用GIS空间分析技术以30 m分辨率栅格绘制了长沙市域内建设用地的扩张变化图。采用等扇分析法作为基础模型,选取了城市空间扩张强度和紧凑度作为主要参数,研究了长沙市城市空间的演变规律。结果表明:长沙城市发展具有"南北纵向扩展为主、东西轴向扩展为辅"的态势;用地扩张系数大幅超前于常住人口增长速度,向东、向南和北偏西为建设用地的强势扩张方向;城市建设用地紧凑度总体在研究期内呈大幅下降趋势,在快速城镇化的进程中建设用地增长的集约性未能充分体现。

Based on the historical raster data of land satellites on the Google Earth platform,this paper extracted and mapped the annual distribution of construction land in Changsha from 1978 to 2018. Using equal fan analysis method as the basic model and 30-meter resolution raster as the analysis unit, and selecting the urban space expansion intensity and compactness as the main parameters, this paper applied GIS spatial analysis technology to studying the regular pattern of urban space evolution in Changsha. The results show the urban development of Changsha has a trend of "north-south vertical expansion as the main and east-west axial expansion as the supplement";"Land expansion coefficient is ahead of population growth rate";"The direction of strong expansion is eastward,southward and west-north".The overall compactness of Changsha City is showing a downward trend,and the decline is relatively large. The rapid growth of the city and its intensiveness have not been fully reflected. The conclusion of this study divides the spatial characteristics of the historical form expansion of Changsha into four stages and they are affected by natural environment,population growth,urban planning and major strategic decisions.