Governments use the green cover ratio and the greening ratio of roadside areas as indicators for evaluating the green cover of residential areas. However, these indexes are based only on the existence of vegetation and do not fully reflect the uneven distribution of vegetation or the diversity of its growth status. In this study, effects are examined using high-resolution satellite images, which are expected to be used for maintenance and management, including the continuity of vegetation as an indicator. As a result, an index value reflecting the vegetation condition was proposed by relating the gravity model for relating vegetation cells on the analyzed images to the NDVI value indicating the vegetation activity of the cell itself, and its effectiveness was confirmed in comparison with previous index values. The proposed index value was used to evaluate the vegetation environment in Senri New Town in Osaka Prefecture by dividing the streets into those including roadside trees and those not including roadside trees in each district, and its effectiveness was discussed.