基于GIS和DEA的三峡库区城镇建设用地变化与效益评价

Analysis of the Changes and Assessment on the Efficiency of Urban Construction Land in Three Gorges Reservoir Area Based on GIS and DEA

城镇建设用地空间扩展是城镇化发展的首要体现,建设用地结构和数量的变化都会对建设用地的使用效益带来一定的影响。本文利用2000和2005年三峡库区土地利用图,采用ArcGIS技术,分析了三峡库区城镇建设用地与其他地类在空间上的转换情况。由于城镇建设用地扩展,耕地面积锐减,耕地向城镇用地转换面积达到6004.77hm2,并且平均图斑面积达到115.48hm2。本文对比了城镇建设用地在扩展过程中占用农用地的区域差异,城镇扩展年占用农用地的面积较多的区域是巴南区、江北县和重庆市区。以河流为中心,建立缓冲区分析城镇建设用地扩展的强度,在缓冲区半径0～10km范围内是库区城镇建设用地扩展的重点区域。结合城镇建设用地的变化分析,采用DEA模型,从库区城镇建设用地效益值、DEA有效性、规模效益的角度,对建设用地效益展开了评价,并采用ArcGIS技术将效益值、DEA有效性、规模效益空间化,研究表明库区城镇建设用地效益值较高的区域分布在库区下游区、重庆市区,城镇建设用地效益整体上在提高,并且区域之间的差距在逐渐缩小。并根据评价情况,对库区城镇建设用地效益提出了建设性建议。

Spatial expansion of urban construction land is a primary expression of urban development,and the changes of structure and quantity of construction land will impact the using efficiency of construction land.This paper utilized the land use maps of the Three Gorges Reservoir Area of the years 2000 and 2005,and ArcGIS to analyze the spatial transformation between urban construction land and other land use types in the region.The expansion of urban construction land has led to a rapid reduction of cultivated land.Some 6004.77 hm 2 cultivat-ed land were transformed into urban land.The average area of plots reached 115.48 hm 2 .The paper analyzed the regional difference in occupying agricultural land for urban development.In the region of Banan District,Jiangbei County and Chongqing urban area,comparatively larger area of agricultural land is occupied each year.Ri-parian buffer was established to analyze the intensity of urban land expansion.In the reservoir area,urban land expansion mainly lies within a radius of 0-10 km from the buffer zone.Combining the analysis of the changes in urban land use,adopting DEA model and assessing construction efficiency by applying efficiency value,DEA validity,and scale efficiency,we made a benefit evaluation of construction land use,and used ArcGIS to spatialize efficiency value,DEA validity and scale efficiency.The study showed that the urban construction lands with high efficiency values were distributed in the downstream reservoir area and Chongqing urban area.The overall efficiency of urban construction land is improving,and the disparity among regions is gradually narrowing.Finally,this paper gave some suggestions on improving the efficiency of urban land use in the reservoir area.