Green Roofs

This dataset and corresponding map provide the location, satellite images and square footage of existing green roofs within the City of Chicago. This information is derived from an analysis of high-spatial resolution (50cm), pan-sharpened, ortho-rectified, 8-band multi-spectral satellite images collected by Digital Globe’s Worldview-2 satellite. The City supplied the consultant with a 2009 City boundary shapefile to determine the required extent of the imagery. Acquisition of three different strips of imagery corresponding to the satellite’s paths was required. These strips of imagery spanned three consecutive months and were collected in August 2010 (90% coverage), September 2010 (5% coverage) and October 2010 (5% coverage). The results of the analysis include overall count of vegetated roofs, their total square footage, and the ratio of required to elective vegetated roofs. A total of 359 vegetated roofs were identified within the City of Chicago. The total square footage of these vegetated roofs was calculated to be approximately 5,469,463 square feet. The ratio of required vegetated roofs to elective vegetative roofs was 297:62 (~5:1). The median size of the vegetated roofs was calculated to be 5,234 square feet.

本数据集及其对应映射提供了芝加哥市现有绿色屋顶的位置、卫星图像和面积信息。该信息来源于对Digital Globe公司Worldview-2卫星所采集的高空间分辨率（50厘米）、全景锐化、正射校正、8波段多光谱卫星图像的分析。芝加哥市政府向顾问提供了2009年的城市边界Shapefile文件，以确定图像所需的范围。根据卫星轨迹，需要获取三条不同图像带，这些图像带跨越了连续三个月的时间，分别在2010年8月（覆盖率90%）、2010年9月（覆盖率5%）和2010年10月（覆盖率5%）进行采集。分析结果包括植被屋顶的总数、总面积以及必需植被屋顶与可选植被屋顶的比例。在芝加哥市内共识别出359个植被屋顶，这些植被屋顶的总面积约为5,469,463平方英尺。必需植被屋顶与可选植被屋顶的比例为297:62（约5:1）。植被屋顶的中位面积为5,234平方英尺。