Research On Walking Accessibility Evaluation And Layout Optimization Of Urban Park Green Space Based On Improved Ga2SFCA

Park green space is not only an important part of the urban ecosystem,but also a major place to meet the needs of urban residents for close to nature,leisure and recreation.With the continuous advancement of urbanization in China and people’s understanding and pursuit of green,low-carbon and healthy lifestyles,the planning,construction and optimization of park green spaces have received more and more attention from the society.Accessibility is an important method to judge the rationalization degree of park green space layout.At present,there are a variety of quantitative methods for the accessibility of park green space,among which Ga2 SFCA has become one of the best methods for the accessibility measurement of park because of the comprehensive consideration of both ends of supply and demand,distance attenuation and simple operation.However,this method often uses a fixed search radius when calculating the accessibility,which is simple but not precise enough.Therefore,elastic search radius should be applied to simulate the actual travel of urban residents more accurately,so as to establish the dynamic accessibility model of urban park green space.This paper takes Xicheng District of Beijing as an example,takes community parks and urban small parks closely related to urban residents’ daily walking travel mode as the research object,constructs the evaluation model of park green space comprehensive service ability and attractiveness respectively from the perspective of government planning and the perspective of urban residents’ visiting,and proposes the method of variable search radius.Then,Ga2 SFCA based on fixed search radius and variable search radius,was used to analyze the walking accessibility of green space in parks.The paper will be elaborated from the following four parts:The first part is the introduction to the thesis.Firstly,the relevant concepts of park green space,accessibility,and Gaussian 2-step floating catchment area method proposed in this paper are defined,and then the literature related to the measurement method of urban park green space accessibility is sorted out,and the key problems to be solved in this paper are proposed.Finally,the research method,content and technical framework adopted in this paper are determined,and the research ideas and logic of the whole paper are summarized as a whole.The second part is related theory research and the construction of improved method system based on Gaussian 2-step floating catchment area method.Under the guidance of accessibility theory,analytic hierarchy theory,individual difference theory and other theories,the comprehensive service capability and attractiveness evaluation models of park green space were constructed respectively,and the search radius of Gaussian 2-step floating catchment area method could be changed.Then,according to the idea of "basic data acquisition--measurement method improvement--evaluation model construction--accessibility operation--application process construction",the complete construction process of the method system is elaborated,and applied to the measurement analysis of the accessibility of park green space.The third part is an empirical study on the walking accessibility of park green space based on the Gaussian 2-step floating catchment area method with variable search radius,including the third and fourth chapters of the paper.The third chapter analyzes the supply and demand status of park green space and resident population in Xicheng district.The fourth chapter evaluates the walking accessibility of park green space in Xicheng District respectively based on the fixed search radius and the modified Gaussian 2-step floating catchment area method,and compares the two methods.Finally,based on the accessibility evaluation of the improved method,a reasonable spatial pattern planning strategy for park green space is proposed.The results show that the latter can reduce the error of space accessibility,and reflect the walking accessibility of park green space more truly and accurately.This method is universal,and can also provide a reference for the research of space accessibility of other public service facilities.The fourth part is the conclusion.Based on the research content,the main conclusions of this paper are obtained,and the innovation and shortcomings of the research work of this selected topic are expounded,as well as the prospects and assumptions for future research.