Urban Expand Research Of Xuejiawan In The Twenty Years

Nowdays the economic develop rapidly, studying on character and driving force of urban expand and proposing optimized allocation of landuse countermeasure had great significance to city health and sustainable development. Xuejiawan located in the junction of three provinces among Shanxi, Shaanxi, and Mongolia, located in the Economic Golden Triangle of Baotou, Hohhot and Ordos. Xuejiawan is the political, economic and cultural center of Ordos Zhungeer County. Study on urban expand in Xuejiawan has important reference value to the zhungeer even the entire western region.In this paper, the study area used Xuejiawan's Ring Expressway and the urban construction land area in 2008 for reference to determine the scope of the study area. TM and ETM remote sensing data in 1987,2002,2008a were used to study urban expand in Xuejiawan by 3S technology. The results showed that:(1) during 1987 to 2008, in the process of urban expansion in Xuejiawan, in addition to forests area, water area and the urban construction land area grew, other land-use types decreased. Various types of land-use have varying degrees of transformation to the phenomenon of urban construction land, woodland and pasture land for urban construction is the main source of expansion. The reduction in pasture, forest land mainly changed into farmland and urban construction land.(2)The urban construction land expanded significantly in Xuejiawan from 1987 to 2008, respectively 329.94ha and 2681.41ha, and showed accelerating trends. This paper took the cross point of the Zhungeer road and Kaiyuan road as the center did the analyze of the urban expand of space quadrant and position, it indicate that on the whole the main trend of urban construction land expand is due south.The main direction of urban construction land expand is due east, southeast, southwest. However,the trend of north is more slowly, that is the expansion of urban construction land in due north, northeast, due east three directions was slow.The analysis of the urban expansion mode based on buffer showed that intensity index of 1987-2002 expansion showed a maximum at a distance of 1km, the extension strength index of 2002-2008 which was at a distance of 2km appeared the first peak, then it reached the maximum at a distance of 6km。As a result, Xuejiawan and the new road district formed gradually "a city of two-center" structure, and showed extension mode which was along the main roads,and town layout which relied on the tour mode of development zone.Driving factor can be summarized as natural geography factor and socio-economic factor. Natural geography factor is basis of urban expand in Xuejiawan, such as topography, geology and water resource, etc. Socio-economic factor is an important driving factor for urban expand, such as urban population increase, economic development, development zone construction, traffic condition, etc. The main direction of urban expand was decided by natural geography factor. Urban expand is mainly to south. North should be controlled. East and west should be developed moderately. The potential, direction, speed, pattern and space structure of urban expand were directly affected by socio-economic factors.