借鉴潜能模型,综合考虑小城镇到县级经济中心的可达性和到周边农村聚落的可达性,构建小城镇综合可达性模型。利用该模型计算了荆州市93个小城镇的综合可达性指数,在此基础上,对小城镇的综合可达性与农村聚落空间格局的关系进行了分析,结果显示:小城镇综合可达性值与邻近分配区内农村聚落总面积、农村聚落平均面积、农村聚落占景观面积比例均呈显著正相关关系,而与邻近分配区内农村聚落数量、农村聚落密度相关性不显著;可达性好的小城镇最容易吸引较大规模的农村聚落在其周边集聚,但小城镇的可达性水平也并不是影响农村聚落分布的唯一因素。可达性等级较差和差的小城镇,因周边耕地和水源条件优越,也吸引了中等规模和中等数量的农村聚落分布。

Referring to Potential Model, combing small town's accessibility to county economic centers and small town's accessibility to nearby rural settlements, an integrated accessibility model of small towns was built. Using this model, values of integrated accessibility index of 93 small towns in Jingzhou were calculated in this paper. Small town's accessibility was classified into 5 levels-excellent(>80), superior(60-80), medium(40-60), inferior(20-40) and poor(<20) according to the values of the integrated accessibility index. Based on the correlation analyses between small town's integrated accessibility and rural settlement landscape indexes in small town's nearby allocation area, as well as the comparison of the average values of rural settlement landscape indexes in the nearby allocation areas of small towns with different accessibility levels, this paper also studied the relations between small town's accessibility and rural settlement distribution. The results are as follows:small town's integrated accessibility shows significantly positive correlation to the total area of rural settlements, the average area of rural settlements and the area percentage of rural settlements in the landscape, but it doesn't show significant correlation to the number of rural settlements and the density of rural settlements in the nearby allocation area; small towns with excellent accessibility are more likely to attract large numbers of settlements with larger scales distributing around them. However, small town's accessibility is not the only factor that influences rural settlement distribution. Small towns graded with inferior or poor accessibility but with large quantity of fertile arable land or water resources still attract moderate numbers of rural settlements with medium scale distributing nearby.