Urban Green Space Layout And Optimization Based On Fairness Discrimination

The construction of ecological civilization and residents’ willingness to improve their living environment require that the layout of green space should be optimized in urban planning and development.As the main source of urban residents’ contact with the green environment,green space can provide a variety of ecological services.The form of green space includes all kinds of vegetation,open space,parks and other green elements in the city,among which the city park plays an important role with its diversified and perfect ecological services.This paper extracts the boundary of urban built-up areas in Beijing as the research object using POI data,starting with two dimensions: the global green space and urban park,using the green exposure,buffer and accessibility analysis,the gini coefficient and lorenz curve to measure urban overall green space fairness distribution in the crowd from quantitative fairness,space fairness and social justice.At last,matching fairness results of global green space with urban park to find out the unreasonable place,then targeted green space layout optimization suggestions are provided as reference for ecological city construction.The specific conclusions of the study are as follows:(1)Quantitative equity analysis of global green space.The coverage rate of green space in the built-up area is 40.55%,which gradually increases from the city center to the outside.From the perspective of green space pattern,the green space in the city has a high degree of fragmentation,low degree of aggregation and relatively complex shape.The exposure of green space is higher in the center and lower in the periphery,while the exposure of green space at the circle-scale shows a trend of lower inside and higher outside,among which the exposure of green space between the fourth and fifth rings is the highest.(2)Analysis on the service level and accessibility of urban parks.Urban parks serve more than 90% of the built-up area and serve more than 92% of the population.There are many service blind spots between the third and fourth ring roads.In terms of service level,63% of the built-up areas of Beijing are at the general service level,and only 2% are at the high-quality service level.The spatial distribution of the spatial accessibility of urban parks is basically manifested as the high accessibility area centered on the urban park,the secondary accessibility area formed in a certain range around the park,and the poor accessibility area appeared in the edge area.From the perspective of urban circle,the spatial accessibility of urban parks decreases from the center to the periphery.(3)Results of social equity in green space.The results of global green space and urban park’s overall social equity are quite different.The Gini coefficient of global green space is 0.501,which is in a wide range.The overall Gini coefficient of urban parks is 0.271,which is in a relatively average category.The spatial distribution of location entropy of the two shows different characteristics.(4)Suggestions on urban green space optimization.Based on the matching results of global green space and urban park,the paper puts forward some suggestions on the optimization of green space layout.Specifically,the number of parks and the construction of small and micro green space should be increased in the areas where the accessibility is higher than the green space coverage.In the areas where the accessibility is lower than the coverage of green space,park service facilities should be improved,road network density should be enhanced,and urban park service scope and service level should be improved.