Delineation Of Urban Growth Boundaries Based On Markov-FLUS Model

China is in a key period of urbanization and industrialization transformation,and the process of urban land expansion is expected to continue.The urban land expansion will exerttremendous pressure on land resources and the ecological environment.Therefore,how to govern the spread of urban land,guide the reasonable expansion of urban land,and improve the efficiency of urban land use have become an urgent problem to be solved.In urban growth management,urban growth boundaries,as an effective tool for achieving smart growth,can help protect the ecological environment,protect basic farmland and reduce urban infrastructure costs,which is of great significance for achieving sustainable urban development.Compared with plain cities,mountainous cities have fragile ecological environment,heavy load capacity of environmental capacity,high ecological sensitivity,less space for construction,and more likely to destroy ecological environment and encroach on farmland during urban expansion.Therefore,explore the growth of mountainous cities.The management method and study of the growth boundary of mountainous cities not only have important theoretical significance,but also have exemplary effects on other mountainous cities facing urbanization development and transformation.In this context,this paper takes the boundary between rigid and elastic urban growth as the main line,taking the main urban area of Chongqing,a typical mountain city in China,as an example.From the perspective of geography,landscape ecology and urban-rural planning.Based on the land use data of the main urban area of Chongqing in 2015,combined with administrative divisions,DEM data,traffic road network data,demographic economic statistics,urban POI point data and various thematic data,using GIS technology,corrosion expansion algorithm and construction The Markov-FLUS model analyzes the characteristics of land use change and spatial pattern evolution in the main urban area of Chongqing during the period from 2000 to 2015,delineating the rigid urban growth boundary of the main urban area of Chongqing,and delineating the main urban areas of Chongqing in 2020 and 2025.The annual growth of flexible cities provides a scientific basis for urban growth management.The main conclusions of the paper are as follows:(1)Analyzed the land use quantity structure and temporal and spatial evolution characteristics of the main urban area of??Chongqing.(1)In terms of quantity structure,the land types in the main urban area are mainly forest land and cultivated land,accounting for 70%of the main urban area,followed by construction land,from4.21%in 2000 to 18.98%in 2015,and the proportion of other land use is maintained.Within 10%;(2)From the perspective of the transfer between land and land,construction land,cultivated land and forest land are the most active land transfer,and the construction land has increased by 229.97 km~2in 2000 to 1037.59 in 2015,the increase reached 451%,the cultivated land decreased sharply.In 2000,2,291.14 km~2fell to 1460.98 km~2 in 2015.The forest land showed a steady growth trend.The growth of construction land mainly stems from the conversion of forest land and cultivated land,and the policy of returning farmland to forest.The conversion of sloping farmland into forest land is also the cause of the increase of forest land and the continuous reduction of cultivated land.(3)From the direction of gravity shift and distance,the center of gravity of construction land first moves to the north-east direction 4.55 km,and then continues to move north-north.2.72 km,and finally moved to the southeast by 0.62 km.The trend of the center of gravity of the construction land reflects the key development direction of urban construction in the main city of Chongqing;(4)from the perspective of land use Pattern analysis results,the number of construction land(NP)plaque showed an increasing trend,and the patch density(PD)increases,the patch shape(AWMSI)tend to be more complex,increasing the degree of fragmentation.(2)Constructed the Markov-FLUS model to simulate land use change in the main urban area of Chongqing.(1)Based on the 2000 land use data simulation 2005 land use data,the simulated data and actual data are compared to obtain a kappa coefficient of0.8374,and the overall accuracy is 0.8984;(2)based on the 2005 land use data simulation 2010 land use data,simulation The data is compared with the actual data to obtain a kappa coefficient of 0.8537 and an overall accuracy of 0.9055.The constructed Markov-FLUS model has high simulation accuracy and is suitable for simulating the future land use distribution pattern in the main urban area of Chongqing.(3)Demarcation of the rigid urban growth boundary in the main urban area of Chongqing.The rigid UGB area in the main urban area of Chongqing is 3654.97 km~2,accounting for 66.86%of the total area of Chongqing's main urban area,mainly distributed in the“four mountains and two rivers”,urban parks and basic farmland coverage areas.(4)Delineated the growth boundary of the elastic city in the main urban areas of Chongqing in 2020 and 2025.(1)In 2020,the area of elastic UGB is 966.05 km~2,accounting for 17.68%of the main urban area of Chongqing.(2)In 2025,the total area of flexible UGB in Chongqing's main urban area is 1163.22 km~2,accounting for 21.28%of the total area of Chongqing's main urban area.