This dataset consists of 2-dimensional roof outlines ("roofprints") for all buildings larger than 150 square feet, as initially 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 by Rolta were enhanced by MassGIS using Normalized Digital Surface Models (NDSMs) derived from the same LiDAR data. Other layers were used, including the Standardized Parcels, to aid in review, especially where LiDAR data were not available.

In 2019, MassGIS refreshed the data to a baseline of 2016 and continues to update features using newer aerial imagery that allows MassGIS staff to remove, modify and add structures to keep up with more current ground conditions. Structures from the original compilation that are removed are stored in an "archive" feature class for edit tracking and historical purposes. Also in 2019, MassGIS replaced the polygons in Boston with data from the city. In March 2021, the layer was updated with 2017 and 2018 structure review edits along with the first data edits compiled atop spring 2019 imagery. Updates based on 2019 imagery were completed in July 2021.

Last updated on 7/1/2021.

In ArcSDE the layer is named STRUCTURES_POLY.