基于夜间灯光数据的西安市城市扩张及驱动因素研究

Study of Urban Expansion and Driving Factors in Xi’an City based on Nighttime Light Data

城市扩张信息的动态监测对了解城市社会经济活动以及城市规划的实施与反馈有重要意义。以DMSP/OLS夜间灯光影像为数据源,采用有理函数模型和阈值二分法对城市扩张数据进行校正和提取,运用灯光指数、城市空间扩展速率和强度指数以及重心迁移相关指数对1993～2013年西安市城市扩张情况进行分析。结果表明:西安市城市建成区面积从1993年的148 km^2增长到2013年的473 km^2,扩张了2.2倍;城市扩张方向从西南发展为南北同步扩展,空间扩张方式也从早期的单核同心扩展模式逐渐转变为多级核生长扩展模式;使用灰色关联度模型分析了2008～2013年西安市近郊四区(未央区、雁塔区、灞桥区和长安区)社会经济指标与城市用地的关联度,发现各区关联度最大指标分别为工业产值(0.474 7)、人口密度(0.731 2)、第三产业产值(0.425 8)和全社会固定资产投资(0.404 5)。

The dynamic monitoring of urban expansion information is of great significance to understand the social and economic activities of cities and the implementation and feedback of urban planning.Using DMSP/OLS night-time light image as data source,the urban expansion data were corrected and extracted by using rational function model and threshold dichotomy.By using the light index,urban spatial expansion rate and intensity index and the index of center of gravity migration,The results show that the urban built-up area in Xi’an has expanded 2.2 times from 148 km^2 in 1993 to 473 km^2 in 2013.The direction of urban expansion expands from southwest to south and north,and the spatial expansion mode also increases from the early stage The single-core concentric expansion mode gradually transformed into a multi-level nuclear growth expansion mode;thus using gray relational analysis to analyze the socio-economic indicators of the suburbs in Xi’an in 2008~2013(Weiyang district,Yanta district,Baqiao district and Chang’an district) It is confirmed that secondary industry,population density,tertiary industry and fixed assets of the whole society are the main driving factors of urban expansion in four districts respectively.