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

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.