Study On Spatial Layout Evolution And Optimization Of Rural Residential Area In Low Mountain And Hilly Area

At present,under the background of coordinated urban-rural development,the rapid progress of urbanization and the construction of new socialist countryside,rural land use is facing enormous pressure and challenges.However,for a long time,due to the lack of planning and management,as an important part of rural land use,the construction of rural settlements is a spontaneous choice of farmers,which directly leads to the scattered layout and piecemeal scale of rural settlements,resulting in idle and inefficient land use and other problems,wasting limited land resources and making contradiction between urban and rural land supply and demand more serious.To study the evolution and optimization of the spatial layout of rural residential land use is of great significance to solve the current problem of land use in rural residential areas and to realize the optimal allocation of land resources and coordinated urban-rural development.This study takes Tongshan County,Xianning City,Hubei Province as the research area,based on the survey database of land use change,DEM elevation data,social and economic statistics data and other text data of Tongshan County in 2009 and 2017 and with the help of software such as ArcGIS?GeoDa?Fragstats and so on.First of all,the scale evolution,spatial distribution evolution and landscape pattern evolution of rural settlements in Tongshan County are analyzed to reveal the spatial evolution characteristics of rural settlements;Secondly,quantitative analysis is used to study the impact of natural and socio-economic factors on the layout of rural settlements;Finally,the rural residential areas in Tongshan County are classified and the strategy of optimizing layout is put forward for each type by evaluating the suitability of rural residential land and combining with the planning of urban land use in Tongshan County.The main findings are as follows:The spatial distribution and evolution of rural residential areas include three aspects:In terms of the scale evolution,the scale of rural residential areas in Tongshan County has expanded.The change of scale and the trend of land use of rural residential areas in each township also show some spatial differences;In respect of the evolution characteristics of spatial distribution,the high value area of nuclear density of rural residential areas in Tongshan County is mainly distributed in the central area of the whole county.The two main high value areas confront each other from east to west.The high value area of nuclear density of rural residential areas at the secondary level is consistent with the distribution trend of rivers and reservoirs.From the spatial autocorrelation analysis,the land scale of rural residential areas in Tongshan County has spatial positive correlation.The characteristics of agglomeration in 2009-2017 have been enhanced but the spatial agglomeration and correlation are low.In 2009,the scale of rural residential land in Tongshan County did not form obvious cold spot area and hot spot area.The hot spot area in 2017 is scattered in many towns,which indicated that the rural residential area in Tongshan County shows the trend of agglomeration;With regard to the characteristics of landscape pattern evolution,the land use of rural residential areas in Tongshan County shows a trend of expansion.The average area of patches decreased,the density of patches increased and the area weighted average patch fraction dimension of most towns increased slightly,which indicates that the whole rural residential areas in Tongshan County tends to be fragmented.The mean shape index of most towns changes little and the shape is relatively stable.By studying the relationship between rural settlements distribution and natural and socio-economic factors in Tongshan County,it is found that the spatial distribution of rural settlements in Tongshan County has obvious characteristics of lowland directivity.With the increase of altitude,the scale of rural settlements is decreasing;nearly 90%of rural settlements are located below 15° on flat and gentle slopes;The rural settlements in the east slope and southeast slope are more than the other slopes and are the least distributed on the plane;The farther away from the rivers and reservoirs,the smaller the scale is,which shows the obvious characteristics of rivers and reservoirs directivity;In the range of 8000 meters from the roads,the farther the distance,the smaller the scale of rural residential areas is.The roads have certain control over its layout but the control is weaker than the factor of rivers and reservoirs.The farther away from the town,the smaller the scale of settlements in Tongshan County is.From 2009 to 2017,the rural residential areas in Tongshan County shows the trend of agglomeration to low altitude area,small slope area,south and east slope,area near rivers and reservoirs,both sides of road and formed town.Meanwhile,the patches of rural residential area also show the trend of fragmentation.By constructing the evaluation index system of land suitability of rural residential areas,the land suitability of rural residential areas in Tongshan County is evaluated.The results are divided into high,moderate,low and unsuitable according to the comprehensive scores.Combined with the planning scope of urban land use in Tongshan County,the rural residential areas in Tongshan County are divided into five types:urbanization type,urban-rural joint type,active development type,controlled development type and relocation type.Finally,the strategies of optimal layout are proposed for each type of rural residential area.