Measuring the quality of public open space using Google Earth

Background Proximity to public open space, such as parks and other green spaces, has considerable health benefits, and people have been shown to be more likely to use such space for physical activity if it is of high quality. This paper describes a new remote-assessment approach that makes use of Google Earth Pro (the free version of this program is Google Earth) to provide rapid and inexpensive measurement of the quality of public open space. Purpose The aim of the study was to assess the correlation between assessments of the quality of public open space using (1) the remote method (making use of Google Earth Pro) and (2) direct observation with a well-established measure of quality, the Public Open Space Tool (POST). Methods Fifty parks selected from the southwest part of Sydney, Australia, were assessed in 2009 with the remote method (using Google Earth Pro), and scores were compared with those obtained from direct observation of the same parks using POST. The time taken to conduct the assessments using each method was also recorded. Raters for each method were blind to scores obtained from using the other method. Analyses were conducted in 2009. Results The Spearman correlation coefficient between the quality scores obtained for the 50 parks using the remote method and direct observation was 0.9 (p<0.0001). The remote method took 4 hours, whereas direct observation took 42 hours, showing the remote method to be much faster and more resource efficient for the measurement of the quality of physical activity-related environments. Conclusions The remote-assessment method provides, for the first time, the capacity to assess the quality of large numbers of parks and other green spaces without the need for in-person visits, dramatically reducing the time required for environmental audits of public open space.