Hydrographic surveys support a variety of activities: nautical charting, port and harbor maintenance (dredging), coastal engineering (beach erosion and replenishment studies), coastal zone management, and offshore resource development. Most surveys are primarily concerned with water depth. Of additional concern is the nature of the sea floor material (i.e. sand, mud, rock) because of the implications for anchoring, dredging, structure construction, pipeline and cable routing and fisheries habitat. (NOAA Office of Coast Survey)NOAA NGDC service information:The corresponding NOS Hydrographic Surveys map service displays the footprints of the hydrographic surveys, along with additional metadata and links to obtain the data. Tiled: https://gis.ngdc.noaa.gov/arcgis/rest/services/web_mercator/nos_hydro/MapServerDynamic: https://gis.ngdc.noaa.gov/arcgis/rest/services/web_mercator/nos_hydro_dynamic/MapServerFor information about NOS Hydrographic Survey Data at NGDC, please see: http://ngdc.noaa.gov/mgg/bathymetry/hydro.htmlUNH-CCOM\JHC service information:Information about UNH Center for Coastal and Ocean Mapping field activity can be found online at http://ccom.unh.edu/theme/law-sea. Please visit the CCOM’s Law of the Sea Downloads Webpage for download of this data as a ESRI grid, Fledermaus SD file, or ASCII file. The web services found in this document can be found here: https://maps.ccom.unh.edu/server/rest/services.