基于GIS的干旱区绿洲农村居民点格局演变研究:以甘肃河西地区为例

A Study on Evolution of Rural Settlements Pattern of Oasis in Arid Area Based on GIS:A Case of Hexi Area in Gansu Province

以甘肃河西地区农村居民点为例,结合GIS技术,运用单一动态度、景观格局指数、平均最邻近指数及核密度方法,对近30 a来农村居民点空间格局演变特征进行分析。结果表明:(1)近30 a来河西地区农村居民点用地规模缓慢增大,居民点斑块个体之间的集聚性增强,结构愈发紧凑。(2)农村居民点空间分布在整体上呈集聚模式。敦煌市、肃州区、甘州区、高台绿洲尾闾区、民乐县西部、凉州区和民勤县城周边居民点分布较密集。(3)居民点集中分布在海拔1 200～2 400 m、坡度<5°的走廊平原和盆地以及坡度较小的缓坡地,在海拔较高的丘陵、山区以及坡度较大的陡坡地居民点分布则相对较少。居民点集中分布在距离县道及以上级别道路1 km范围内,河流对居民点分布的影响在1～6 km范围内较显著。(4)受政策和经济利益的调控和驱动,人类生产生活方式不断改变并作用于居民点,直接或间接导致农村居民点格局演变。

Taking the rural settlements of Hexi area in Gansu Province as an example,the spatial pattern evolution characteristics of rural settlements in the past 30 years of the area were analyzed using single dynamic degree index,landscape pattern index,average nearest neighbor index and nuclear density method.The results show that:(1)The scale of rural settlements in the Hexi area increased slowly,and the agglomeration of settlement patches enhanced.The structure became more compact.(2)The spatial distribution of rural settlements is agglomerated overall.The rural settlements are densely distributed around Dunhuang City,Suzhou District,Ganzhou District,Owase District of Gaotai Oasis,Minle County,Liangzhou District and Minqin County.(3)The rural settlements are concentrated in corridor plains and basins,and gentle slopes with the elevation of 1 200-2 400 m and gradient<5°.Less settlements are distributed in relatively high elevation hills,mountain areas,and areas with relatively steep slopes.The settlements mostly lie within 1 km in distance to the county roads and the roads above county level.The rivers have a significant impact on the distribution of rural settlements within the range of 1 to 6 km in distance.(4)Due to the regulation and urging of policies and economic interests,the production and lifestyle are constantly changing and influencing on rural settlements,which directly or indirectly leading to the evolution of rural settlements.