Research On The Change Of The Land Use For Urban-rural Construction In Harbin Based On Remote Sensing

With the rapid rate of urbanization,the scale of urban-rural construction land and the proportion of impervious land surface have increased significantly along with problems such as the unreasonable internal structure and layout,which are serious threats to the protection of cultivated land and the safety of the ecological environment.The"three-line"delineation and protection have attracted much attention.The changes of urban-rural construction land have important influence on urban development.They are one of the most direct manifestations of land use/cover changes caused by human activities.They are the main reflections of changes in land use patterns during the transition process between urban and rural areas,and they are important features and driving forces for the development stage of urban-rural integration.The research on impervious surface changes will further quantify the changes in the internal structure of urban-rural construction land.Obtaining these changes could provide foundation for improve the management and control mechanism,and optimizing layout,promote the development of new urbanization and urban-rural integration,and play an important role in the management of land us,urban and rural construction,and urban-rural layout optimization.As an important city for the revitalization and the development of the northeast,Harbin is both an old industrial and a big agricultural city,hence it has the distinct structure of urban and rural areas at the same time.This article focuses on the six districts of Harbin,Daoli,Daowai,Nangang,Pingfang,Songbei,and Xiangfang,where urbanization has developed rapidly.The impervious surface extraction based on the VIS+shade model provides a strong technical support for multi-level three-dimensional dynamic monitoring of remote sensing.This paper applies the"National Land Use 1:10 Million Database"and Landsat remote sensing images,using remote sensing technology to quickly obtain more accurate land use data of 2000,2005,2010,2015 land and the impervious surface date with a correlation coefficient(R~2)of 0.906 in 2005,2015.According to the development of urbanization and land science,geographical science theory,space statistical analysis,dynamic degree,relative change rate,transfer matrix analysis were used to analyze the temporal and spatial characteristics of land of urban-rural construction and its internal impervious surface in Harbin,and to explore the regional differences and pattern changes in the process of urban-rural development,and following main conclusions were made:(1)The characteristics of the change and source of the scale and structure of urban-rural construction land:(1)During 2000-2015,the urban-rural construction land in Harbin city is expanded by 158.32 km~2,with a dynamic degree of 2.51%.The expansion rate is larger and shows an increase and then a decrease.The dynamics of the three stages are 1.97%,2.55%,and 2.22%.(2)During 2000-2015,urban construction land and independent industrial and mining lands have been expanding year by year,reached 57.65%and 18.67%respectively by 2015;Land use in rural residential areas first increased and then decreased,accounting for only 23.69%by 2015;Among them,independent industrial and mining lands have the greatest changes,followed by urban construction land,and rural residential land changes little.(3)The main source of urban-rural construction land expansion is cultivated land,which poses a serious threat to cultivated land protection.In addition,some rural residential lands and independent industrial land are taken for urban construction,and their structures and functions gradually converge to urban construction lands.It is an important representation of urban-rural transformation and urban-rural integration.(2)Regional differences in land use for urban and rural construction:(1)During 2000-2015,the construction land in urban and rural areas in Songbei District is highly expanded,which is53.17 km~2,followed by Xiangfang and Daoli District.The construction land in Pingfang,Nangang and Daowai District changes little.(2)During 2000-2015,the change speed of urban-rural construction land in the Pingfang area is the fastest,with a dynamic degree of 5.40%,followed by Songbei,Xiangfang and Daoli District.The changes in Daowai and Nangang District are slow.Among them,the rate of urban and rural development in Pingfang and Songbei Districts was faster,and the change was greater than that in the whole region,the relative change rates were 2.15 and2.11 respectively.(3)The proportion of urban construction land in all regions is increasing,and the ratio of rural residential land use is decreasing.Moreover from practical perspective,the boundaries of the city’s core area will continue to expand.(4)From the urban core area to the distant suburbs,the expansion of urban-rural construction land area is increased in turn,but its land use rate is decreased in turn.And with the advancement of the urban and rural development process,the focus of regional urban and rural construction continues to shift towards the urban suburbs,and continues to develop in the direction of urban-rural integration,forming the pattern of the mixture of city and countryside.(3)The changes of impervious land surface in urban and rural construction land:(1)During2000-2015,the total area of impervious surface is increased by 143.00 km~2,the proportion of impervious surface is increased by 15.43%,and the expansion intensity is 1.03%.Among them,the surface area of impervious land for urban construction land has the largest increase,but due to its relatively advanced construction,the expansion strength is the minimum of 0.51%.As the country continues to increase its efforts in rural construction,its impervious surface expansion intensity is raised to 1.78%.(2)During 2000-2015,the impervious surface expansion strengths in Daowai,Songbei,and Daoli District are relatively high,1.32%,1.24%,and 1.21%respectively.The other three areas are lower.(3)During 2000-2015,the increase in the proportion of impervious land for urban construction land is greater in Daowai and Songbei District.The increase in the proportion of impervious surface land in rural residential areas is greater in Xiangfang and Nangang District.The proportion of impervious land surface in independent industrial and mining areas has increased significantly in Daoli and Daowai District.It demonstrates that the construction priorities of each jurisdiction are different.(4)Changes of impervious surface in different urban locations:(1)The intensity of land use decreases from the urban core area to the far suburbs,but the expansion intensity shows an opposite trend.The main reason is that the closer it is to the core area of the city,the more perfect its pre-construction is and the smaller space it has for reconstruction.(2)The urban construction land near the suburbs has the highest impervious surface expansion intensity of 1.10%,followed by the core area,the far suburb area,and the fringe area,indicating that the urban construction in the suburbs has developed most rapidly in recent years.In addition,the land use intensity in the core area is still constantly increase.(3)From the urban fringe area to the outer suburbs,the intensity of impervious surface expansion of rural residential land is decreasing.It can be seen that the development of integrated urban and rural areas will give priority to the development of rural areas close to the urban core area.(4)The independent industrial and mining land near the suburbs has the largest impervious surface expansion intensity,followed by the far suburbs,and the marginal area has less increase,which indicates that the suburbs near the city has the highest rate of development of the independent industrial and mining construction,and that the development of independent industrial and mineral construction in the urban fringe area is limited because of the control of urban development.