Analysis Of The Relationship Between Railtransit And Urbanform

Along with the advancement of world urbanization,On the one hand,the trend of urbanization is significant in big cities,mainly for the concentration of population is Occurring in the big cities and megacities.At the same time,growth of the proportion of the population of large cities is continues;On the other hand,the developed countries have entered the stage of post-urbanization,and the developing countries and regions have become the centers of rapid urbanization,especially in Asia,the continent with more than 60%population of the world,large cities,metropolitan areas are constantly evolving.The rapid accumulation of population to the big cities has created a series of space problems,such as:(1)Because of the space supply and demand does not match,resulting in traffic jams;medical care,education and other public facilities are also insufficient;(2)urban centers are extremely crowded;rapid and extensive using of land outside the city makes low efficiency,and also the commuting distance is extend;(3)natural space,green space is occupied,the city livability is declining.On the other hand,the low-density and flattening expansion of City suburb is confronted with the hard constraints of finite time resources in one day,which leads to the contradiction between time and space and restricts the development of large cities.The objective needs of space development in metropolitan development and the objective existence of contradiction between time and space make it necessary to explore the rationality and sustainability of urban form from the perspective of time and space.It also makes time become a dimension that cannot be neglected in modern urban development.Based on the theory of spatio-temporal economics,this paper holds that the city is a field with spatial and temporal scales,including all kinds of elements and system relations.Through the stratified analysis of the spatio-temporal distribution of cities,the paper points out key elements which affect the urban form and its sustainable development in different space-time scales.The paper tries to find a way to meet the space demand of the metropolis and solve the contradiction between time and space,and also try to construct a sustainable urban form.In this paper,the space-time hierarchy of urban form is divided as follows:(1)Immediate space-time,refers to the individual space travel trajectory and time cost.This time and space scale changes the fastest.The main factors which affecting it are organization and technical factors;(2)short-term space-time,refers to the individualliving and working space for a period of time,such as buying a house makes the basic travel time and space be determined.The spatial and temporal scale change speed is relatively fast,and the main influencing factors are the supply and demand of urban traffic and living space.(3)medium-term space-time refers to the formation of regional functional areas.This spatial and temporal scale changes slowly,the main influencing factors are urban land use planning and traffic planning.(4)Long-term space-time refers to the formation of urban morphology evolution.The spatial and temporal scale changes the slowest,and the historical process of natural geography,industrialization,urbanization and transportation,and the influence factors of all the above-mentioned dimensions affect the development of this scale.Temporal and spatial changes in the short-term,immediate obey the rule of the medium and long term scale movement.while instantaneous space-time changes,accumulation,as part of the long-term space-time,affecting the coordinated development of long-term stability.This paper argues that the relationship between traffic and land use is the key factor which influence the shape,efficiency and boundary of urban field.Transportation is one of the most important parts of urban area,and there is an interaction mechanism between urban land use and space-time evolution.The traffic demand is caused by land use,and the transportation network is constructed because of land use.At the same time,the improvement of traffic accessibility to users and area affects the efficiency of individual movement,the coordination of relationship between time and space,individuals living and working location choice in short time,and then lead to factor mobility,agglomeration,changing land use at last.In this paper,we define the traffic location field and the people,resources and interrelationships which adsorb on it as a traffic economy field.In the traffic economic field,because of the capacity,speed and reliability of the dominant traffic system are different from those of other systems;the influence on the accessibility of users along the space is also different.For all these reasons boundary and efficiency of the field are different.In summary,the interaction mechanism between traffic,land use and their interaction is the main reason for the change of spatial and temporal scale of urban form,and also the key factor influencing the rationality and sustainable development of urban form.In the long run,it is the coherence of transport and urbanization which promotes socio-economic and civilized development;and modern metropolitan disease is largely affected by the development of the urban land use,unreasonable development of traffic and the uncoordinated of their relationship.The objectivity that more people and less land determines the irrationality of decentralized development of large cities.it is not economic and unsustainable to keep dispersion,low density development in large cities.Compact space,vertical expansion,land intensive utilization and Three-dimensional transport have become a feasible even inevitable choice.Based on the existing contradiction of space and time and the sustainable development demand for future,the mass transportation,a rapid,land saving,energy saving and environmental protection mode of mass transit become the only effective way for the sustainable development of modern large cities.The technology,industry and space-time economic characteristics of the rail transit network match up with the characteristics of the vertical compact city concentration.Through the rail transit network,the ground traffic and vertical traffic,the three-dimensional traffic network and vertical space docking,users and regional accessibility are greatly enhance,and further promote the development of the region along the railway in vertical compact mode.Thus the formation of high-density,high efficiency rail economic field will be made.The space gain of the rail economic field is as follows:(1)space saving,land intensive using,integration of space function,shortening of travel space distance,vertical expansion of underground and ground space,horizontal extension of space,equalization of space function,and the like.(2)The time gain of the rail economic field is:time resource saving;travel time value enhancement;free time multiplication and so on.(3)The space-time relationship gain of the rail economic field is as follows:space-time relation construction;space-time relation transformation;space-time relation solidification.By integrating rail transit and land use,it is possible to break through the space constraints in the development of large cities under certain time constraints,and to expand the efficiency boundary of large cities and improve the coordination between cities and nature and promote the sustainable development of large cities.Through the integration of rail transit and city land use,the paper point out specific strategy to build rail economic field:(1)the dynamic consistency of planning;(2)Optimizing the shape of rail transit network,coupling with urban space;(3)the central area of rail hub complex building;(4)Synchronous development of suburban rail transit area..The development of both Tokyo and Hong Kong has fully utilized the interactive mechanism between rail transit and land to build a vertical,compact and efficient urban form in the rail transit hub and along the rail transit hub.This has become a model for the healthy and sustainable development of high-density metropolitan areas.The main conclusions of this paper are as follows:(1)Time is an important dimension in urban form,spatial limitation;space-time contradiction and spatial-temporal coordination are the key factors affecting modern metropolis sustainable development.(2)The.temporal and spatial distribution of urban space has the characteristics of stratification.The development of short-term and immediate space-time should be in accordance with the long-term spatial and temporal coordination.(3)The spatial and temporal scales of urban form are impacted by transit.The interaction mechanism between traffic and land use,the scale and efficiency of traffic economic fields are the key factors affecting the scale and efficiency of urban areas,and the large-scale urbanization trend shows the efficiency of large cities.Urban disease is not because of city size,but mainly because of unreasonable urban land use and uncoordinated transportation development.(4)Based on the existing space-time contradiction and constraints,to rail transit-oriented three-dimensional traffic network is the effective and only way to solve the big city traffic problem.On the one hand,it can realize the compact and intensive use of urban land,expand the space vertically and break through the space constraint;on the other hand,it can realize a large number of demands for fast and punctual Space-time conversion,and build a solid,coordinated relationship in a larger space to breaking the space constraints.The ultimate goal is to build sustainable three-dimensional urban form based on rail transit network,and keep the city field running high efficiency.