Research On Zhejiang Provincial Urban System Based On The Night-light Data From DMSP/OLS

With the wave of globalization,the reform and opening-up policy gradually in-depth,the rapid growth of urbanization in China is unprecedented.The high rate of urbanization is bound to enhance the connection between towns.Therefore,the urban research can not be confined to a single town.It needs based on the a group of towns that have an organic connection between economic and social and spatial development namely the urban system.American military weather satellites Defense Meteorological Satellite Program carry sensor Operational Linescan System has high ability of photoelectric magnification can detect light,fire,fishing boat lighting and other human activities.It is a kind of good urban research data sources?which can be used in urban development,human activities and Ecological environmental impact.Compared with the traditional statistics,it has the advantages of objectivity and space.This paper through a case study of Zhejiang Province because of the high level urbanization,based on the non radiometric calibration night-light data from the Defense Meteorological Satellite Program(DMSP)Operational Linescan System(OLS).The research used method such as the information extraction of remote sensing image,GIS spatial analysis,GIS network analysis and spatial interpolation to extract urban spatial index and evaluate urban system.Aimed at Overcoming the flaws in the statistics on urban system research.Mainly from the following two aspects are studied.First,comprehensive urban built-up area statistics data,use the Stastistics-assisted Thresholding which is one of the Thresholding method to derive the urban built-up areas.After improving the method through the regression equation,it can derive the urban built-up areas which are in the lack of statistics data,Besides,presents a new light index—the Correct Regressive Total Night Light Index(CRTNLI)which can describe the urban development.CRTNLI has obviously positive correlation with statistical data,therefore it is reliable data to research the urban system.Second,research the urban system of Zhejiang Province with CRTNLI in 1993,2003 and 2013.According to the gravity of the towns,Zhejiang province can be divided into a total of five urban systems:Hangzhou,Ningbo,Taizhou,Wenzhou,Jinyi.Compare with Gu's empirical study of China's urban system,the results is compellent.From the level of urban scale,traffic network,agglomeration and natural geography Angle comprehensive analysis of the five urban system.The result shows that,first,Hangzhou urban system and Ningbo urban system are advanced and mature with traffic developed,wide radiation area,frequent urban relations and the core cities form a metropolian area.Second,the scale of Wenzhou urban system and Taizhou urban system are smaller.The towns and the traffic network focus on the east coastal belt plain.There are lots of differences between east and west.Third,Jinyiqu urban system is lack of core cities.Towns are concentrated in the Jinqu basin and urban relations are weak.It is an immature urban system.Finally,there are obviously high correlation between the urban system and the terrain or the river.