Research On Landscape Evaluation And Optimization Strategy Of Urban Greenway In Nanjing

Greenway is an important linear open space in the urban green space system,which plays an important role in maintaining the ecological environment,improving the urban style and characteristics,protecting the historical and cultural heritage,and satisfying the residents’ leisure needs.China has set off a wave of greenway construction,Nanjing has also carried out a bold attempt and exploration.By 2022,1,782 km of urban greenways have been built in Nanjing,but whether the actual results of greenway construction meet the design expectations remains to be tested.To evaluate the greenway landscape,judge the value of the landscape and quantify it is conducive to improving the construction status,improving the quality of the greenway landscape,and providing reference for the future greenway landscape construction and promotion.Therefore,based on the investigation of the construction status of urban greenway in Nanjing,this study uses Scenic Beauty Estimation(SBE)and Analytic Hierarchy Process(AHP)to conduct landscape evaluation.Combined with the investigation and evaluation results,this study summarizes the landscape characteristics of urban greenway in Nanjing,analyzes the existing problems and deficiencies of greenway landscape,and proposes corresponding optimization strategies.The main research contents and results are as follows:(1)Field investigation: Taking forest landscape greenway,cultural landscape greenway and waterfront recreation greenway as objects,the current situation of the trail system,green plants and facility system of the greenway was investigated.The results show that the route layout of Nanjing urban greenway is single,the connectivity is insufficient,and there are hidden dangers.Lack of application of green plant species,lack of management and conservation;The number of facilities is insufficient,the type is not complete,the layout is not reasonable.Nanjing greenway needs further optimization and improvement in trail system,green plants and facility system.(2)Evaluation research of Scenic Beauty Estimation(SBE): SBE was used to evaluate 8urban greenways in Nanjing.Firstly,a questionnaire is used to investigate the general public to obtain the beauty value and order it.Secondly,the image semantic segmentation technology is used to decompose the landscape elements and calculate the value of each element.Finally,the relationship between the beauty value and each element is analyzed through correlation analysis.The ranking results of beauty degree value are: Crescent Lake Park Greenway > Hydrangea Park Greenway > Purple Mountain Greenway > Xuanwu Lake Greenway > Moat Greenway > Peach Garden Greenway > Ming City Wall Greenway > Qinhuai River Greenway.The results of landscape elements showed that vegetation was the most important visual element of greenway,accounting for 56.89%.Correlation analysis showed that sky openness,greenness,plant hierarchy,plant color richness and plant growth were highly correlated with beauty value.(3)Evaluation research of Analytic Hierarchy Process(AHP): Landscape evaluation of 8urban greenways in Nanjing was carried out through AHP.Firstly,18 evaluation indexes were selected to construct the landscape evaluation system of Nanjing urban greenway based on basic recreation level,natural ecological level,spiritual culture level and landscape aesthetics level.Secondly,by asking experts to obtain the weight value of each evaluation index,Nanjing urban greenway landscape evaluation model was obtained.Finally,quantitative data were obtained through field survey and qualitative data were obtained through questionnaire,and comprehensive landscape evaluation value was obtained and sorted and graded.The evaluation results show that the overall landscape of urban greenway in Nanjing is level II.The ranking results were: Crescent Lake Park Greenway > Hydrangea Park Greenway > Xuanwu Lake Greenway > Purple Mountain Greenway > Ming City Wall Greenway > Moat Greenway > Peach Garden Greenway > Qinhuai River Greenway.(4)Optimization strategy research: According to the field investigation and the analysis results of the two evaluation methods,the landscape characteristics,existing problems and deficiencies of urban greenways in Nanjing are summarized.At the macro level,the optimization strategy of Nanjing urban greenway landscape is proposed from four aspects: ecology,recreation,landscape and culture.At the micro level,the design points of three types of greenways: forest landscape greenway,cultural landscape greenway and waterfront recreation greenway are summarized from three aspects: trail system,green plants and facility system.In this paper,a variety of research methods such as field research,Scenic Beauty Estimation(SBE)and Analytic Hierarchy Process(AHP)are used to make a comprehensive analysis of Nanjing urban greenway landscape and put forward targeted optimization strategies for its existing problems,in order to improve the quality of Nanjing urban greenway landscape and provide scientific basis and practical reference for future greenway construction.