不同尺度下街道空间绿化品质测度研究与提升策略——以杭州市中心城区为例

Research on urban street greenery quality measurement under different scales and promotion strategy——A case study of Hangzhou’s main urban area

以杭州市中心城区为例,基于百度街景与遥感影像数据源,利用图像识别算法与遥感影像解译,从人本与遥感2种尺度分别测度城市街道空间绿化品质,获得街道绿视率与绿化覆盖率2项指标。对二者总体的空间分布特点与空间上的相关性进行分析,结果表明:(1)整体分布上,绿视率与绿化覆盖率在城市空间的总体分布上呈现由西南向北、向东递减的趋势,但在各个区域内具有差异;(2)具体分布上,绿视率与绿化覆盖率在城市空间的分布上并无相关关系。绿视率高而绿化覆盖率低的点位多分布于滨水道路,主要由于狭长的绿化形式以及水体面积干扰等因素引起。绿视率低而绿化覆盖率高的点位多分布于老旧小区周边道路,主要由于道路本身绿化水平较低以及受到遮挡等因素引起。目前基于遥感尺度的绿化覆盖率单一指标难以体现城市居民的真实感受,而增加人本尺度的规划则能更全面地展现城市绿化水平,为提升街道绿化品质提供规划策略。

Taking the Hangzhou’s main urban area as an example,on the basis of Baidu street view and remote sensing image data sources,the study used image recognition algorithm and remote sensing image interpretation to measure the afforestation quality of urban streets from both human-oriented and remote sensing scale,respectively.It aimed to obtain the visible green index(VGI)and vegetation coverage rate.Through analyzing the spatial distribution characteristics and spatial correlation between these two indicators,the results showed that:(1)In terms of the overall distribution,the VGI and green coverage rate in urban areas had been on a downward trajectory from southwest to north and east,but still,it had differences within each region.(2)In terms of the specific distribution,the VGI and green coverage rate in urban space had no correlation.The spots with high VGI and low green coverage rate were mainly distributed on waterfront roads,which were caused by the interference of long and narrow green forms and water body areas.The spots with low VGI but high green coverage rate were mostly located in the streets around old neighborhoods,which were mainly caused by the low afforestation level of the streets themselves and the shading of external greening by buildings.The current green coverage index based on the remote sensing scale was difficult to show the real feelings of urban residents about afforestation.Combining with the consideration of human dimension,the urban green level could be more comprehensively displayed,and the planning strategies for improving the quality of streets greening could be provided.