The data may also be categorized further, based on types of geographic features, such as infrastructure, physical resources, and political boundaries. This page describes the two broad categories. For descriptions on individual layers see the Available Datalayers page, on which the data are organized within the more-detailed categories. Datalayer descriptions may also be found in the MassGIS Catalog .
Units are meters.
Many of the base map datalayers maintained by MassGIS have been derived from U.S. Geological Survey data and represent many of the feature types found on USGS topographic maps. More recently developed data were derived from the digital orthophotos providing improved basemap accuracy. Several of the MassGIS base map features are available in two scales. MassGIS is making increasing amounts of large scale data available which is suitable for spatial analysis within towns or of individual parcels of land. Large scale data have been developed from the EOEA digital orthophotos.