MassDEP Hydrography (1:25,000) (Hosted Feature Layer)

This MassDEP Hydrography hosted feature layer from MassGIS is an enhanced version of the older U.S. Geological survey 1:25,000 Hydrography datalayer. It represents hydrographic (water-related) line and area features, including surface water (lakes, ponds, and reservoirs), wetlands, bogs, flats, rivers, streams, and others. The layer is a hybrid of data based on USGS Digital Line Graphs (DLGs), scanned mylar separates obtained from the USGS, digitized hydrographic features from paper USGS 1:25,000 Topographic Quadrangle maps and data extracted from the MassDEP Wetlands datalayer. Areas within many surface water supply watersheds have been enhanced by using higher resolution streams and lakes from the MassDEP Wetlands datalayer, many areas have also been field verified. See full metadata本由马萨诸塞州地理信息系统（MassGIS）托管的马萨诸塞州环境质量部（MassDEP）水系要素图层，是老旧美国地质调查局（USGS）1:25,000比例尺水系数据图层的增强版本。该图层涵盖水文地理（与水相关）的线状与面状要素，包括地表水（湖泊、池塘与水库）、湿地、沼泽、滩涂、河流、溪流及其他相关地物。本图层的数据来源混合多样：基于美国地质调查局（USGS）数字线划图（DLGs）、从美国地质调查局获取的扫描聚酯薄膜分幅图、纸质美国地质调查局1:25,000比例尺地形分幅地图上数字化的水文地理要素，以及从马萨诸塞州环境质量部湿地数据图层中提取的数据。诸多地表水供应流域内的区域，已通过采用马萨诸塞州环境质量部湿地数据图层中的高分辨率溪流与湖泊数据完成增强优化，且多数区域已开展野外实地验证。详见完整元数据。