Assessing Google Street View Image Availability in Latin American Cities

Dustin Fry,Gina S Lovasi,Stephen J Mooney,Daniel A Rodríguez,Waleska T Caiaffa

doi:10.1007/s11524-019-00408-7

Abstract

Virtual audits using Google Street View are an increasingly popular method of assessing neighborhood environments for health and urban planning research. However, the validity of these studies may be threatened by issues of image availability, image age, and variance of image age, particularly in the Global South. This study identifies patterns of Street View image availability, image age, and image age variance across cities in Latin America and assesses relationships between these measures and measures of resident socioeconomic conditions. Image availability was assessed at 530,308 near-road points within the boundaries of 371 Latin American cities described by the SALURBAL (Salud Urbana en America Latina) project. At the subcity level, mixed-effect linear and logistic models were used to assess relationships between measures of socioeconomic conditions and image availability, average image age, and the standard deviation of image age. Street View imagery was available at 239,394 points (45.1%) of the total sampled, and rates of image availability varied widely between cities and countries. Subcity units with higher scores on measures of socioeconomic conditions had higher rates of image availability (OR = 1.11 per point increase of combined index, p < 0.001) and the imagery was newer on average (− 1.15 months per point increase of combined index, p < 0.001), but image capture date within these areas varied more (0.59-month increase in standard deviation of image age per point increase of combined index, p < 0.001). All three assessed threats to the validity of Street View virtual audit studies spatially covary with measures of socioeconomic conditions in Latin American cities. Researchers should be attentive to these issues when using Street View imagery.

Highlights

Google Street View, a Google Maps service released in 2007, offers freely available georeferenced panoramic imagery captured at the street level [1]
Prior to conducting virtual audit studies, researchers should first carefully evaluate the Street View imagery that is available in the study site, including the spatial patterns of availability and the dates of image capture
If areas of researcher interest have high rates of non-imaged street segments, or if the imagery is not available at time points of interest, measures from virtual audits could be supplemented by other data sources such as in-person audits or ecometric resident surveys [19, 20]

Summary

Introduction

Google Street View, a Google Maps service released in 2007, offers freely available georeferenced panoramic imagery captured at the street level [1]. Researchers note that image resolution can limit the reliable identification of small objects, and that the inability of researchers to control when images are taken limits Street View’s usefulness in assessing variables that can change rapidly over time [3,4,5,6,7,8,9,10]. This suggests that virtual audits are not a good substitution for in-person audits in all cases

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Results

Conclusion