Analysis And Prediction Of Urban Land Expansion In Central Area Of Ordos

With the improvement of urbanization level,the development and utilization mode of urban land will directly affect the growth of city economy and the further expansion of its scale,and also have a great impact on the sustainable development of cities.Because of this,the degree of urban expansion is regarded as an important index to reflect the evolution of urban space.This study takes the central area of Ordos as the research area,and predicts the expansion trend by accurately obtaining the information of its urban land expansion,which is of great significance to guide the urban planning and optimize the urban spatial structure.Firstly,the remote sensing images of 2000,2005,2010 and 2015 are interpreted,the land is classified according to the type of utilization,the mathematical model is constructed to calculate the dynamic attitude index,the transfer matrix and so on to analyze the land use situation in central area,and the area index and expansion intensity index are introduced,The timing variation characteristics of urban land in the group structure of the central area in 2000-2015 years are quantitatively described.The fractal dimension index and the compactness index are introduced,and the expansion mode of urban land is identified by the method of graph Cascade plus visual differentiation.In order to analyze the time-series variation characteristics of urban land used in central area,this paper sets up the scenario scheme of 2006-2020 land use expansion in central area,and uses the SLEUTH model to simulate and predict the long time series of urban spatial expansion by using the Ordos.Finally,according to the research results,this paper analyzes the problems existing in the expansion of urban land in the group structure of the central area,and puts forward some suggestions for sexual suggestion.The results show that:(1)Under the background of rapid improvement of urbanization level,the evolution mode of land use structure in Ordos central area is mainly "woodland-bare land-grassland",and the dynamic change of land use mode is fast in the whole research period.The land use level of Ordos central area is low,the utilization structure is unreasonable,the proportion of bare land is large,although the conversion with other land types is frequent,but the proportion is always the largest;Throughout the study period,land use in the region changed considerably,land use attitude between 48% and 56%.This shows that the regional land use is significantly affected by human activities,resulting in land waste,low level of land use and other issues prominent.(2)Urban expansion is a long-term and complex evolution process,is the economy and population,nature and transportation,planning and policy and many other factors of the comprehensive role and game results.In this paper,the characteristics of urban land expansion change in the group structure of Ordos central area are studied,and from the degree of expansion,in 2000-2015,the urban land area of the group structure in central area continued to increase,and the increase degree of each group area was different,and the scale of the Dong Sheng area was the main growth object.According to the expansion intensity index,the urban land expansion in central city can be divided into three stages: 1)The steady expansion stage with moderate urban expansion intensity(2000-2005),2)the rapid and drastic expansion stage with large urban expansion intensity(2005-2010),3)the low-speed expansion stage with small urban expansion intensity(2010-2015).(3)The morphological changes of urban land use in the group structure of the central area of Ordos in 2000-2015 showed that the fractal dimension index of each group area gradually increased,while the compactness index decreased gradually.With 2005 years as the tipping point,before 2005,the expansion mode of Dong Sheng area was relatively single,showing obvious epitaxial expansion mode,urban form comparison rules but poor stability,urban contour is more compact,the urban form of Kang-A area is regular and unstable,and the urban contour is loosely inclined.After 2005,the expansion mode of Dong Sheng area showed diversification,mainly star-like spread expansion,internal filling type as a supplement,Kang-A area showed a group growth,and Dong Sheng area docking trend is obvious,at the same time,the two polar nuclei around the Dong Sheng expansion group,equipment manufacturing Base Group,Kang-A logistics industry group,has become a new growth area,But the expansion mode is relatively single,mainly star-like spread,the urban form is irregular,the urban contour is scattered.(4)The SLEUTH model can be used to simulate the expansion trend of urban land use to predict the group structure of Ordos central area in the next 15 years.The research shows that the expansion law of the region in the next 15 years is mainly the spontaneous growth model along the boundary of the central area and the new construction land along both sides of the road.From the forecast results,in the next 15 years,the urban land of group structure in central area growth is small,and the main growth area in the Kang-A area.As far as the trend of expansion is concerned,the scale expansion of the two central polar nuclei in central urban area is obvious,and the ability of radiation to expand the expansion of the peripheral groups is increasing,so as to form the development trend of space docking.The development trend of industrial group area is better,and it is closely related to Dong Sheng area and Kang-A area,which may form a new urban growth center.(5)The level of urbanization in central area of Ordos is high,but there are still obvious problems.First,the level of land use is low.The urban land use of the group structure in central area has also triggered the transformation of the soil use mode in the region at the same time,and there are many phenomena such as the disorderly expansion of the development law and the scattered layout of the new construction land.Second,the structure of the three types of industrial land is unreasonable.The types of land used in central area are still dominated by energy,chemical industry,building materials,metallurgy and other secondary industries,which are impacted by domestic and foreign industrial environment and economic environment,resulting in large quantities of industrial land idle.Third,the expansion model is extensive.The central area has basically formed a stripe and decentralized group space expansion model,the north-south integration trend is obvious,but the construction of east and west peripheral groups is unevenly distributed,the degree of land plaque aggregation in each group area is not high,the expansion mode is mostly decentralized urbanization expansion mode.Fifth,each group area space is loosely connected.The two core areas of Dong Sheng and Kang-A are not closely connected,and the phenomenon of low level repetitive construction and disorderly competition appears in each group area,which forms the independent development of the two core areas of the central area and the loose connection with the peripheral groups.