Study On The Relationship Between The Green View Index And Green Plot Ratio Of Urban Streets

Among the numerous measurement indexes of street greening,the three-dimensional green volume index,the green plot ratio,can directly express the intensity of the three-dimensional green volume of the city and reflect the ecological benefits of the site.The index of psychological green quantity green rate can measure the visual ecological quality of street space and directly reflect the effect of green landscape in the space.This paper,taking wuhan city qingshan district street as an example,use 3S technology,Baidu street view map and green view index automatic algorithm,evaluate the current situation of street green view index and street green plot ratio in the study area,discusses the correlation between street green view index and street green plot ratio,hope to further understand the relationship between the intensity and quality of urban street greening,and make suggestions for the renovation work of street greening.The main contents and conclusions of this paper are as follows:(1)Based on the street view picture of Baidu,calculate and evaluate the street green view index of the research area.Half of the street sample spots in the study area have not reached the standard of 25%green vision,and there is still room for improvement in the construction of street greening.The mean and median green vision of the secondary trunk roads and branch roads are all over 25%,when the Greenness of urban expressway is evaluated by street type,the results of the greenness of the street sample are slightly different from the results of the average greenness of the whole street,the results show that there is a disequilibrium phenomenon of street greening,and the rate of green vision of historic culture,landscape leisure,commercial and life service streets decreases in turn,but they are better than those of traffic and comprehensive streets.(2)The leaf area index(Lai)of main streets in the research area was measured and the regression model of street green quantity was established.The best model for retrieving street green is the cubic polynomial model of ratio vegetation index(RVI)Y=1.997-2.481X+1.798X2-0.235X3(R2=0.712).(3)The total green volume of branch roads,secondary trunk roads,arterial roads and urban expressways in the study area were 865882.16m2,791670.98m2,1562517.57m2 and 582371.52m2.The street regional green plot ratio ranked as secondary trunk roads(1.164)>branch roads(0.974)>arterial roads(0.966)>expressways(0.634).(4)Through a series of studies on the relationship between the green view index of the street and the green plot ratio of the street,the results show that the two are highly positively correlated.As one of the factors affecting the green view index,the green plot ratio of the street affects the streets at different levels.However,it can be determined that the street green plot ratio is the main factor affecting the street green visibility.Based on the index of green plot ratio,the optimization strategy of street green view index is proposed.The green view index can theoretically be used as a predictor of street green plot ratio,but it should be graded.The prediction accuracy of branch roads and arterial roads are at medium level.The green plot ratio of elevated urban expressways are not suitable for prediction by this method.