Spatial-temporal Characteristics Of Changes In Construction Land In Jiexiu City And Its Environs

With the development of social economy, the spatial pattern and quantity of land are undergoing dramatic changes, the land use changes and the research on and its driving force have received universal attention. Over the past three years, with the rapid development of social economy in Jiexiu City, the construction land expanded a lot. The analysis of spatial-temporal characteristics of environs in Jiexiu city and its environs and driving mechanism can rationally guide the size and layout of land use structure, thus formulating scientific land policy.The paper took Jiexiu city and its environs as research area, and remote-sensing images in year 1983, 1993,2002 and 2013 were collected. Firstly, the remote-sensing image preprocessing procedure is conducted, including radiation correction, geometric correction, image cutting and image intensification, and the image of research area is obtained. Then, the information on land-use types is extracted. To get the maps of land use types and the area of various land types in the four phases, image classification is carried out by supervised classification method in ENVI software and they were evaluated accurately. The vector overlay analysis is conducted on construction land in the four phases by ArcGIS software. The spatial and temporal variation characteristics of research area are discussed and the quantitative calculation of expansion rate and expansion intensity of construction land is conducted. Finally, this paper analyzed the main driving factors of these changes through regression analysis and principal component analysis. The main conclusions obtained are as follows:l.The construction land scale in the research area expands significantly, and it increased from 10.57 square kilometers in 1983 to 15.42 square kilometers in 1993, from 27.33 square kilometers in 2002 to 40.45 square kilometers in 2013. in the past 30 years, the total area of construction land increased by nearly 4 times. The construction land in the research area showed a rapid expansion.2.The temporal expansion characteristics of construction land shows that,in the three study period,During 1983-1993 and 2002-2013,the expansion rate were 4.59% and 4.36% respectively, they were similar;During 1993-2002,the expansion rate is 8.58% and the expansion rate was the fastest, during this period, the development of economy was rapid. A lot of land was possessed by construction land.From analysis of expansion intensity,the result showed that, During 1983-1993, the expansion intensity was intermediate During 1993-2002 and 2002-2013,the expansion intensity was high-speed.3.Over the thirty years, the spatial expansion of construction land in researched area has shown the following characteristics:construction land expands around in a circled way from the town center, the location of Chengguan township government. The housing estate expands around the town center, and in the east and the south, many industrial and mining enterprises and residents supporting infrastructure increase. The transportation land increased rapidly, and a series of arterial traffics appeared, such as Sanxian Main Road, JingKun expressway, Daxi high-speed rail. The railway and highway was crisscross and they provide huge potential for construction land expands, making the construction land expand on both sides of the transportation land.4.By analyzing the driving factors about the expansion of construction land in researched area, it is indicated that the natural condition in researched area has exceptional advantages, which provides the space for the expansion of construction land. The favorable geographical location and rapid economic development of surrounding areas promote the local economic development and large-scale expansion of construction land. After making quantitative analysis on the relationship between the social and economic development indicators and the area of construction land, it is found that the growth in economy and population, the adjustment of industrial structure and the development of science and technology have the important influence on the expansion of construction land. Among them, gross fiscal revenue, population and the proportion of second industry are the major driving factors about the expansion of construction land in researched area.