摘要
绿地暴露是影响居民休闲步行的关键因素.然而,现有研究尚不明晰绿地暴露的各项指标影响休闲步行的相对重要性、阈值区间及其在职住地的空间异质性.论文基于上海市问卷调查数据,采用梯度提升决策树模型,分别探究了职住地绿地暴露对休闲步行时间的影响程度及阈值效应.研究发现,在绿地暴露指标中,到最近公园距离是预测休闲步行时间的最主要变量.在居住地,到最近公园距离对休闲步行时间的贡献仅次于年龄;在工作地,到最近公园距离、绿色空间供需比、绿地面积的相对重要性排名分别为第6、7、9位.绿地暴露各项指标对休闲步行时间的影响方向在职住地是相似的.到最近公园距离与休闲步行时间具负向关联,主要作用区间为650 m内.当居住地NDVI处于0.10～0.14和工作地绿色空间供需比小于0.2时,两者均与休闲步行时间呈正向关联.绿地面积和公园数量与休闲步行时间呈正向关联且没有明显阈值.这些发现为规划和设计职住地绿色空间以促进休闲步行提供了科学依据.
Abstract
Leisure walking is one of the most important physical activities,and green space exposure is regarded as an important influencing factor of leisure walking.However,previous studies have paid limited attention to the relative importance of each green space exposure indicator to leisure walking,and the threshold effects of green space exposure and the spatial heterogeneity of residences and workplaces.Based on a survey conducted in Shanghai between 2018 and 2019,consisting of 1049 participants,this study used a gradient boosting decision tree approach to explore the threshold effects of exposure to green space around residences and workplaces on the duration of leisure walking.The results show that around both residences and workplaces,among green space exposure indicators,distance to the nearest park is the most important predictor for the duration of leisure walking.Around residences,distance to the nearest park is the second most important predictor and its ranking is only lower than age.Around workplaces,distance to the nearest park is the sixth important predictor,followed by the area of greenspace and the supply-demand ratio of greenspace,ranking seventh and ninth,respectively.Around both residences and workplaces,distance to the nearest park has negative associations with leisure walking when it is lower than 650 m.Beyond this threshold,distance to the nearest park has a trivial contribution to the duration of leisure walking.Value of NDVI around residences,when between 0.10 and 0.14,is positively correlated with the duration of leisure walking.When the supply-demand ratio of greenspace around workplaces is less than 0.2,it has a positive association with the duration of leisure walking.More green areas and parks are positively related to the duration of leisure walking without clear thresholds.With regard to the attributes of the built environment,around both residences and workplaces,land use diversity positively correlates with the duration of leisure walking,while distance to the city center has a negative association with the duration of leisure walking.Population density around residences and the number of transit stops around workplaces are negatively related to the duration of leisure walking with certain thresholds.These findings provide evidence for planning and designing green spaces around residences and workplaces to promote leisure walking.
维普
万方数据