Study On Suitability Evaluation And Optimization Of Rural Settlement Land In Longnan City

This paper discussed the spatial distribution characteristics of rural settlements in longnan city by means of geostatistics and visualization methods;By using raster-weighted superposition method,this paper analyzed the suitability of the land as the rural settlement land and the suitability of the existing rural settlements.According to the above conclusions,the optimization model and development direction of rural settlements in longnan city were proposed,based on GIS.The results showed that:(1)The rural settlement land in longnan city is 41119.19hm~2,the land per capita is 193.95m~2,which is higher than the national land standard.The patch area of 79.25% of the city is less than 0.6hm~2,and the distribution is messy and disorder.Uneven spatial distribution of rural settlements has characteristics of high density area and low density area and there are multiple,central of Huichen Basin is the most populous,The central area of Heba town and jiangxi town of Xihe county is second.,other counties around the citys and towns are also high density value areas but not obvious,south of the city formed a typical low density area under the influence of qinba mountainous.The overall performance is "valley and low hills densely,and the high mountains are sparse".The morphology difference of rural settlements in the whole city is obvious,The settlement patterns in the western part of the city are generally higher than that in the east,The number of irregular settlements is huge.(2)Longnan city land suitability score between 1.36-4.75,the Most suitable,Highly suitable,Moderately suitable,Low-suitable and unsuitable for the area were 186490.49hm~2,434381.71hm~2,745944.93hm~2,8774230.85hm~2 and 541428.52hm~2,respectively,accounting for 6.69%,15.59%,24.48%,31.50% and 19.44% of the total land area.The most suitable areas are mainly distributed in Li County,Xihe County,Cheng County,Hui County and Wudu county with relatively flat topography,developed urban areas,concentrated population and convenient transportation.The area of high fitness is mainly located in the vicinity of the most suitable area,which is located near the road and large rivers.moderately suitable area,low-suitable areas and unsuitable areas are mainly distributed in the southern of city and dangchang county,li county in northwestern steep high altitudes,farm garden lacking,traffic jam,small town influence and farmers' income lower area.The results were superposed with the patch of the rural settlements,got the 5 types of rural settlements accounted for 32.59%,30.46%,24.48%,10.81% and 1.66% of the total area of rural settlements in the whole city.(3)According to the suitability grades,aggregate impact value and the result of weighted Voronoi diagram,put forward four kinds of optimization mode: urbanization,generally scale,limit development-oriented and migration combined type,the area were 2702.75hm~2,22692.42hm~2,13273.07hm~2 and 2450.95hm~2.The corresponding development strategies and suggestions were given.