Assessing street-level urban greenery using Google Street View and a modified green view index

Enhancing community environments to support walking and bicycling serves as a promising approach to increase population levels of physical activity. However, few studies have simultaneously assessed perceptions and objectively measured environmental factors and their relative association with transportation or recreational physical activity. For this cross-sectional study, high- and low-income study areas were selected among census tracts in St. Louis MO ("low-walkable" city) and Savannah GA ("high-walkable" city). Between February and June 2002, a telephone survey of 1068 adults provided measures of the perceived environment and physical activity behavior. In this timeframe, objective measures were collected through environmental audits of all street segments (n =1158). These measures were summarized using 400-m buffers surrounding each respondent. Neighborhood characteristics included the land use environment, transportation environment, recreational facilities, aesthetics, and social environment. Associations were examined between neighborhood features and transportation- and recreation-based activity. After adjusting for age, gender, and education, transportation activity was negatively associated with objective measures of sidewalk levelness and perceived and objective neighborhood aesthetics. It was positively associated with perceived and objectively measured number of destinations and public transit, perceived access to bike lanes, and objective counts of active people in the neighborhood. Recreational activity was positively associated with perceived access to recreational facilities and objective measures of attractive features. These findings indicate that physical activities for transportation or recreational are associated with different perceived and objective environmental characteristics. Modifications to these features may change the physical activity behavior of residents exposed to them.

Research indicates that neighborhood environment characteristics such as physical disorder influence health and health behavior. In-person audit of neighborhood environments is costly and time-consuming. Google Street View may allow auditing of neighborhood environments more easily and at lower cost, but little is known about the feasibility of such data collection. To assess the feasibility of using Google Street View to audit neighborhood environments. This study compared neighborhood measurements coded in 2008 using Street View with neighborhood audit data collected in 2007. The sample included 37 block faces in high-walkability neighborhoods in New York City. Field audit and Street View data were collected for 143 items associated with seven neighborhood environment constructions: aesthetics, physical disorder, pedestrian safety, motorized traffic and parking, infrastructure for active travel, sidewalk amenities, and social and commercial activity. To measure concordance between field audit and Street View data, percentage agreement was used for categoric measures and Spearman rank-order correlations were used for continuous measures. The analyses, conducted in 2009, found high levels of concordance (≥80% agreement or ≥0.60 Spearman rank-order correlation) for 54.3% of the items. Measures of pedestrian safety, motorized traffic and parking, and infrastructure for active travel had relatively high levels of concordance, whereas measures of physical disorder had low levels. Features that are small or that typically exhibit temporal variability had lower levels of concordance. This exploratory study indicates that Google Street View can be used to audit neighborhood environments. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.