Analysis on the structure features and types of the rural settlement in karst mountain:A case in Wushan county,Chongqing

China has entered a new period of building well-off society in an all-around way, which includes karst mountain where is sparing no effort in developing the rural construction level. It is of very important significance to analyze the special spatial distribution characteristics of the rural settlement in karst mountain for optimizing the rural settlement spatial layout and promoting the construction of a new socialist countryside and the integration of urban and rural development. In order to explore the spatial characteristics of the rural settlements in karst mountain, in light of special metrics modles of distribution, dimension and shape,the paper conducts a quantitative analysis on the space differentiation of rural settlements in Wushan county, and further identifies the regional types. The results are as follows. As a whole, in spatial distribution the rural settlements in Wushan are of certain concentrating features but exist obvious regional difference. The rural settlements are of low value congregation features and are small in scale generally. In spatial form, the rural settlements in the west Wushan are characterized by good connectivity and high complex but irregular in shape; those in the east Wushan are characterized by poor connectivity and low complex. Overall, the rural settlements are characterized by low irregular shape in need of planning and adapting. By means of constructing space measurement index system of the rural settlements with the hierarchical cluster method, six types of rural settlement in Wushan are divided as follows: low-density point-scattered type, low-density small-mass type, medium-density stripe type, low-density irregular-mass type and high-density wide band type as well as high-density point-scattered type. Rural settlement reconstruction works in the future should be guided by the characteristics of different types.