Description: This dataset consists of 2-dimensional roof outlines ("roofprints") for all buildings larger than 150 square feet, as interpreted by a contractor (Rolta) for the whole area of the Commonwealth using DigitalGlobe ortho images obtained in 2011 and 2012, supplemented with LiDAR (Light Detection And Ranging) data collected from 2002 to 2011 for the eastern half of the state. The roofprints as delivered were enhanced by MassGIS using Normalized Digital Surface Models (NDSMs) derived from the same LiDAR data. Other layers were used, including the Level 3 Parcels, to aid in review, especially where LiDAR data were not available. In ArcSDE the layer is named STRUCTURES_POLY.