Rooftop area and potential area for rooftop greening in Tokyo metropolitan area are estimated by analyzing polygon data of buildings and digital aerial photographs on geographic information system The followings are the results of this research 1) Rooftop area of buildings for public, commerce, residence and industry in 23 wards of Tokyo is estimated to be 16,491ha 2) The ratio of the potential area for rooftop greening is estimated to be 77 6% on average 3) Potential area for rooftop greening is 4,917ha, about 8% of 23 wards' area These results give important suggestions for planning scenarios of rooftop greening in Tokyo
