Hydrography (1:25,000) (Polygons)

The MassGIS 1:25,000 Hydrography datalayer represents hydrographic (water-related) features, including surface water (lakes, ponds, reservoirs), wetlands, bogs, flats, rivers, streams, and others (see attributes below). The layer is a hybrid of data based on USGS Digital Line Graphs (DLGs), scanned mylar separates obtained from the USGS, and digitized hydrographic features from paper USGS 1:25,000 Topographic Quadrangle maps. This layer had previously contained features from the USGS 1:100,000 hydrography; these have been replaced with features from the scanned mylars. Available statewide, the hydrography (arc and polygon feature classes) is stored in ArcSDE as HYDRO25K_POLY and HYDRO25K_ARC. In the QUAD library the layer is named HYDRO and each coverage is named HD.