  Urban greenery is considered an important factor in relation to sustainable
development and people's quality of life in the city. Although ways to measure
urban greenery have been proposed, the characteristics of each metric have not
been fully established, rendering previous researches vulnerable to changes in
greenery metrics. To make estimation more robust, this study aims to (1)
propose an improved indicator of greenery visibility for analytical use
(standardized GVI; sGVI), and (2) quantify the relation between sGVI and other
greenery metrics. Analyzing a data set for Yokohama city, Japan, it is shown
that the sGVI, a weighted form of GVI aggregated to an area, mitigates the bias
of densely located measurement sites. Also, by comparing sGVI and NDVI at city
block level, we found that sGVI captures the presence of vegetation better in
the city center, whereas NDVI is better in capturing vegetation in parks and
forests. These tools provide a foundation for accessing the effect of
vegetation in urban landscapes in a more robust matter, enabling comparison on
any arbitrary geographical scale.
