| Xi’an is one of the key development cities under the great western development strategy implementation, and is also economic center of northwestern regions, having convenient transportation and advantages of location. For22years, land use status and city space expansion scale have changed dramatically in Xi’an. These led to a series of urban problem, such as population pressure, traffic congestion, regional resources shortage and ecological unbalance and so on. Therefore, it is an important practical significance for solving urban population, resources, environment and urban sustainable development to research this topic.This paper monitored the land use status and urban sprawl evolution of Xi’an using RS and GIS, and using1988,1995,2002and2010yeas of remote sensing image as data sources. And analysis the changes combined with social and economic statistical data of Xi’an. The main conclusions are as follows:(1) Land use change is significantly of Xi’an city in recent22yeasFirst of all, the paper extracted4periods land use information of Xi’an adopting unsupervised and supervised classification, and extracted information of each features types. Secondly, monitoring the land use dynamic change on time and space using land use dynamic, transfer matrix of land use area, sequence on time and space figures. Finally, analysis the driving forces of land use change qualitatively. The results show that:Land use/cover changed obviously of Xi’an from1988to2010year. The most outstanding change of land use is the increasing of construction land and declining of cultivated land in Xi’an city for22years. Construction land increased608.889km2in22years, increased26.677km2every year, and its dynamic is11.162%. This shows that urban and rural construction land is in rapid development stage. Increased construction land occupied mainly cultivated land of high quality in regions of Weiyang, Baqiao, Yanta and Chang’an, leading to the quantity of cultivated land decrease quickly. Cultivated land reduced547.821square kilo meters in total in22years, reduced24.901square kilo meters in annual and its dynamic is1.031%in one year.Except for cultivates land transforming to construction land, parts of them transformed to forest land distributing mainly in the mountain with certain altitude and in qinling mountain of the southern of Chang’an region and on steep slopes of Lintong region. The transformation rate is relatively small among grassland, water and undeveloped land. Average annual variations of land utilization degree are0.371,0.784and1.431at three stages, these show that land utilization degree has been in an intensive development stage, its change is very intense. The main reasons are urbanization and industrialization’s improvement in Xi’an city. And the terrain and hydrological and so on are the secondary factors.(2)The built-up expansion quickly in Xi’an city in nearly22yearsFirst of all, this paper extracted built-up information of Xi’an using NDBI, supervised classification and artificial visual interpreting. Secondly, the paper analyzed the speed, intensity, space differences and the distance from zhonglou of built-up expansion in Xi’an city using stack analysis and mathematical model. Finally, we explored the drive mechanism using correlation analysis, principal component analysis and backward regression analysis. The results show that:The built-up area has increased from123.216square kilo meters to522.287kilo meters between1988and2010year. And built-up area of annual expansion in2002-2010stage is three times in1988-1995.This shows that the Xi’an city’s expansion is in a rapid development stage and has a strengthen trend. The expansion model of Xi’an city is taking the clock tower as center, presenting concentric circles. The three center regions of Lianhu, Beilin and Xincheng are priority to their inner construction, and four nearby regions of Yanta, Weiyang, Baqiao and Chang’an are priority to expansion outward, and its expanding rate is faster than the speed of three centers expansion. On the whole, the biggest expansion strength center of Xi’an city is away from tower one to two meters at each stage, and expansion intensity place are the transitional belts on the outskirts of the town. These changes are mainly caused by economic, transportation, population, fixed assets investment and policies and regulations.(3)The driving force is obvious between urban land and other types of land in Xi’an cityWith the development of economic, the human changed the landscape information of the earth’s surface at an unprecedented speed. The rapid expansion of urban has caused the transformation of land use patterns, at the same time the rationality of the land use patterns will restrict the sustainable development of a city. So people should deal with the relationship between the land use and urban expansion in order to make city develop healthy and sustainable. Correlation analysis and multiple regression analysis results show that economic development is the root of the city expansion, traffic is a guilding role in the city’s expansion, the population is the direct cause of the city expansion and fixed assets investment policies and regulations are contributed to the city expansion.Urbanization and industrialization level is the main reasons of the city land use type change.There are some advices for future urban of Xi’an planning. They are keeping the historical and cultural city status, constructing the function of more central areas, developing vigorously the public service facilities and strengthening the function of suburban town centers and so on, so that it can be harmonious development among population, resource and environment of Xi’an city. |
PDF Full Text Request