Development and assessment of the second generation National Building Statistics Database

The second generation National Building Statistics Database (NBSD2) has been computed from a set of three dimensional building datasets for 44 cities in the United States. The building datasets used to derive the NBSD2 are smaller than the complete metropolitan area, but are centered on the important tall building districts. The majority of the datasets were either obtained from commercial vendors (e.g., i-cubed, Vexcel, Inc., Urban Data Solutions) or extracted from airborne lidar data by the National Geospatial-Intelligence Agency (NGA) using a set of tools created by Science Applications International Corporation (SAIC) in collaboration with the Defense Threat Reduction Agency (DTRA). A couple of datasets were developed internally at the University of Utah. The following building statistics are included in the NBSD2: mean building height, standard deviation of building height, plan-area-weighted mean building height, height histograms, plan area fraction, plan area density (at 1-m height increments), building roof area density (at 1-m height increments), frontal area index, frontal area density (at 1-m height increments), building surface-to-plan area ratio, complete aspect ratio, height-to-width ratio, sky view factor, roughness length, and displacement height. Several of the parameters are computed as a function of wind direction (north, northeast, east, and southeast being the standard four directions included). To compute these parameters, the Urban Morphological Analysis Processor (UMAP) tool developed by researchers at the University of Utah was used. UMAP is a code developed to process three-dimensional building and tree datasets to compute urban canopy parameters. The NBSD2 provides the building statistics at 250-m and 1-km horizontal spatial resolution in a variety of file formats. It is available on CD from the first author. This paper summarizes the development of the NBSD2 and quantifies trends and variability of building statistics across the cities, regionally, and in the United States for use in mesoscale meteorological and dispersion modeling applications.