BGVI: A New Index to Estimate Street-Side Greenery Using Baidu Street View Image

Xinyang Yu,Chunyan Chang,Fang Heng,Xiujie Yuan,Gengxing Zhao

doi:10.3390/f10010003

Abstract

The significance of street-side greenery monitoring is increasing for precise urban planning and environmental management, especially in rapid sprawling urban cities, while there have been few studies focusing on urban greenery estimation using new profile image system. In this study, Baidu Street View (BSV) images, which were taken by Baidu vehicles and had view angles similar to those of pedestrians on the street, were selected for calculating the magnitude of street profile greenery. From 278 randomly selected street sample sites in Tai’an city of China, 3336 images were acquired via the Baidu Application Programming Interface (API). A Baidu Green View Index (BGVI) was proposed to quantitatively describe the street-side profile greenery. The results demonstrated that green vegetation can be distinguished efficiently from BSV images. The BGVI varied in the different portions of the study area, and it can be used to grade street system by considering pedestrians’ visualized greenery. Though BGVI had a significant correlation with the overlooking green canopy coverage, in some street sample sites it can delineate different scenarios. BGVI can be regarded as complementary information to urban planning and management.

Highlights

Urban street-side greenery has long been one of the most prime landscape design factors in urban ecological system (e.g., [1,2])
Twelve Baidu Street View (BSV) images were acquired to stitch a continuous image of image of a streetscape in representative urban area of Tai’an city, and a Baidu Green View Index (BGVI) was proposed to a streetscape in representative urban area of Tai’an city, and a BGVI was proposed to quantitatively quantitatively describe street-side greenery, which was found to be fit for representing the street-side describe street-side greenery, which was found to be fit for representing the street-side greenery that greenery that pedestrian can see on the street
Imagery can be used to extract used to extract overlooking biophysical information such as covering area of green canopy, above ground biomass, and leaf area index (LAI), etc., which are helpful in understanding the urban green overlooking biophysical information such as covering area of green canopy, above ground biomass, and leaf area index (LAI), etc., which are helpful in understanding the urban green system, choosing appropriate urban vegetation, and adjusting the urban green ratio according to urban planning concepts

Summary

Introduction

Urban street-side greenery (e.g., street tree, shrub wood, grass, etc.) has long been one of the most prime landscape design factors in urban ecological system (e.g., [1,2]). It can synthesize oxygen [3,4], mitigate urban heat island effect [5,6], and help to increase peoples’ esthetic feelings [7,8] in vision aspects, offering the opportunity of improving peoples’ health and welfare [9,10,11]. An overhead view from RS images may omit the grass or shrub under the canopy cover, which is the scene pedestrians on the ground can see at the street side (Figure 1)

Results

Discussion

Conclusion