Study On Optimization Of Urban Park Green Space Layout Based On Accessibility Evaluation

With the development of urban economy and the improvement of people's life quality,the outdoor recreation behavior of urban residents is increasingly diversified,which puts forward higher requirements for urban outdoor space.Park green space not only affects the ecological environment of the city,but also a very important factor,as a kind of outdoor public space,closely related to the life of all citizens.At present,new construction concepts such as "ecological livable city" and "park city" have been put forward to push the urban green space into the scientific and refined development stage.Under this context,how to measure the construction level of urban park green space in order to make this kind of infrastructure serve the general public better,is an important content to be considered in urban green space renewal and construction.Accessibility as an indicator that can reflect the space layout mode and the service efficiency,can measure the convenience degree of the residents' arrival to the park,the rationality of the park layout and the fairness of service,so it is paid a great attention by the scholars and applications.A variety of quantitative evaluation methods are derived by information technology,but there're respective limitations that lead to the gap of analysis results between the reality.In addition,most related studies focus on a certain type or local area scope,which is not enough to reflect the overall situation.In view of the shortage of the city park layout research and application of evaluation methods,this paper based on the evaluation methods of spatial accessibility,use the space syntax theory that can reflect individual subjective perception of space and then produce activity behavior as well as the network analysis in GIS that can simulate the convenience to reach space under actual transportation,with six districts in Tianjin city as the research scope,on the current layout of four kinds of parks comprehensive quantitative evaluation.The research process includes four sections:background,basic research,modeling calculation and result application.Chapter one elaborates the research background and current situation,defines the study object and method and forms the research idea and framework.The second part introduces relevant concepts,theories and technical methods,moreover,sorts out the basic dataof the research area.Modeling calculation includes calculating the multi-variable accessibility of the park by using the space syntax and the service scope of the park with four traffic modes in corresponding time,more importantly,finding the blind area of the park service.According to the evaluation results,we found following issues : The spatial distribution of parks in Tianjn center city is disequilibrium;regional differences in accessibility is large;parks' layout and spatial accessibility with poor adaptability of population density;spatial accessibility are not match with park type;many residents can not reach the park in a short walking time;there are many park service bling area under the transportation;traffic road network affects park accessibility etc.Based on the above problems,the paper puts forward corresponding reasonable suggestions and optimization strategies,such as the improvement of urban traffic network construction;planning parks in combination with population density and space accessibility;the service blindness compensation;increasing the park attraction;introducing the quantitative evaluation methods to improve the evaluation system of urban park green space.Hoping to provide suggestions for the optimization of the park green space system in Tianjin city in the new period and provides reference for the efficient urban public space and infrastructure construction under the context of ecological livable development of Chinese cities.