The National Bathymetric Source (NBS) project creates and maintains high-resolution bathymetry composed of the best available data. This project enables the creation of next-generation nautical charts while also providing support for modeling, industry, science, regulation, and public curiosity. Primary sources of bathymetry include NOAA and U.S. Army Corps of Engineers hydrographic surveys and topographic bathymetric (topo-bathy) lidar (light detection and ranging) data. Data submitted through the NOAA Office of Coast Survey’s external source data process are also included, with gaps in deep water filled through Global Multi-Resolution Topography, a merged model of bathymetry. Different vertical datums and file formats are made available to meet various uses. The BlueTopo folder includes multilayer floating point GeoTIFFs with associated Raster Attribute Tables (RAT) containing elevation, vertical uncertainty, with other quality metrics and source information. These files are arranged in a spatial tiling and resolution scheme corresponding to the Electronic Navigational Chart (ENC) but are not for navigation due to the inclusion of additional non-navigation data and non-navigation vertical datums. For navigational datasets please see the S-102 distribution portal. "nowCOAST" provides public access to BlueTopo through the nowCOAST viewer, web map tile services (WMTS), and links to individual datasets.

The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Association (NOAA) to interpret the surficial geology in estuaries along the coast of the northeastern United States. The purpose of our present study is to interpret the distributions of surficial sediments and sedimentary environments in an area of Narragansett Bay using sidescan sonar imagery, high-resolution bathymetry, and sediment data. The mosaic presented herein covers an area of the sea floor in central Narragansett Bay. The mosaic and their interpretations (represented in part by this data layer) serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan sonar mosaics also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.

THIS MAP IS NOT AUTHORITATIVE. SEE TERMS OF USE BELOW.This web map contains data layers reflecting the current status of bathy data coverage in the nearshore (0-80 meters) of the U.S. Great Lakes, including acquisition (lidar and multibeam sonar), ground-truthing/validation, and benthic habitat mapping and characterization. Acquisition layers include coverage areas that have been acquired and are available for public use (green) as well as those that have been acquired, but are not yet available or are still in progress (orange). The nearshore water depth layers (0-25 and 25-80 meters) were created using the National Centers for Environmental Information (NCEI) Great Lakes Bathymetry (3-second resolution) grid extracts. The 0 to 25 meter nearshore water depth layer represents areas where bathymetric lidar data acquisition could ideally be conducted, depending on water condition and turbidity. The 25 to 80 meter layer shows locations where acoustic data acquisition can occur. See below for information on additional data layers. All data originally projected in the following coordinate system: EPSG:3175, NAD 1983 Great Lakes and St Lawrence Albers.This map will continue to be updated as new information is made available.Source Data for Bathy Coverage Layers - Acquired/Available:Topobathy and Bathy Lidar (NOAA's Data Access Viewer: https://coast.noaa.gov/dataviewer/#/; U.S. Interagency Elevation Inventory (USIEI): https://coast.noaa.gov/inventory/). Multibeam Sonar (National Centers for Environmental Information (NCEI) Bathymetric Data Viewer: https://www.ncei.noaa.gov/maps/bathymetry/; NOAA's Data Access Viewer: https://coast.noaa.gov/dataviewer/#/; U.S. Interagency Elevation Inventory (USIEI): https://coast.noaa.gov/inventory/; USGS ScienceBaseCatalog: https://www.sciencebase.gov/catalog/item/656e229bd34e7ca10833f950)Source Data for Bathy Coverage Layers - GLRI AOIs (2020-2024):Acquisition: NOAA Office for Coastal ManagementValidation/CMECS Characterizations: NOAA National Centers for Coastal Ocean Science (NCCOS)Source Data for Bathy Coverage Layers - In Progress and Planned:NOAA Office of Coast Survey Plans: https://gis.charttools.noaa.gov/arcgis/rest/services/Hydrographic_Services/Planned_Survey_Areas/MapServer/0NOAA Office for Coastal ManagementSource Data for Nearshore Water Depths:NOAA's National Centers for Environmental Information (NCEI) Great Lakes Bathymetry (3-second resolution) grid extracts: https://www.ncei.noaa.gov/maps/grid-extract/Source Data for Spatial Prioritization Layers:Great Lakes Spatial Priorities Study Results Jun 2021. https://gis.charttools.noaa.gov/arcgis/rest/services/IOCM/GreatLakes_SPS_Results_Jun_2021/MapServerMapping priorities within the proposed Wisconsin Lake Michigan National Marine Sanctuary (2018). https://gis.ngdc.noaa.gov/arcgis/rest/services/nccos/BiogeographicAssessments_WILMPrioritizationResults/MapServerThunder Bay National Marine Sanctuary Spatial Prioritization Results (2020). https://gis.ngdc.noaa.gov/arcgis/rest/services/nccos/BiogeographicAssessments_TBNMSPrioritizationResults/MapServerSource Data for Supplemental Data Layers:International Boundary Commission U.S./Canada Boundary (version 1.3 from 2018): https://www.internationalboundarycommission.org/en/maps-coordinates/coordinates.phpNational Oceanic and Atmospheric Administration (NOAA) HydroHealth 2018 Survey: https://wrecks.nauticalcharts.noaa.gov/arcgis/rest/services/Hydrographic_Services/HydroHealth_2018/ImageServerNational Oceanic and Atmospheric Administration (NOAA) Marine Protected Areas (MPA) Inventory 2023-2024: https://www.fisheries.noaa.gov/inport/item/69506National Oceanic and Atmospheric Administration (NOAA) National Marine Sanctuary Program Boundaries (2021): https://services2.arcgis.com/C8EMgrsFcRFL6LrL/arcgis/rest/services/ONMS_2021_Boundaries/FeatureServerNational Oceanic and Atmospheric Administration (NOAA) U.S. Bathymetry Gap Analysis: https://noaa.maps.arcgis.com/home/item.html?id=4d7d925fc96d47d9ace970dd5040df0aU.S. Environment Protection Agency (EPA) Areas of Concern: https://services.arcgis.com/cJ9YHowT8TU7DUyn/arcgis/rest/services/epa_areas_of_concern_glahf_viewlayer/FeatureServerU.S. Geological Survey (USGS) Great Lakes Subbasins: https://www.sciencebase.gov/catalog/item/530f8a0ee4b0e7e46bd300dd Latest update: February 19, 2025

This is an image service providing a shaded relief visualization of bathymetric/topographic digital elevation models stewarded at NOAA's National Centers for Environmental Information (NCEI). This service provides a color shaded relief visualization of the data; for elevation/depth values in meters, please see the related DEM Global Mosaic (Elevation Values) or DEM Mosaic (Individual DEMs) services.

The DEM Global Mosaic is an image service providing access to bathymetric/topographic digital elevation models stewarded at NOAA's National Centers for Environmental Information (NCEI), along with global and regional grids such as GEBCO_2019, IBCAO, IBCSO, and the Hawaiian Island Multibeam Synthesis (University of Hawaii). This service provides a color shaded relief visualization, for elevation/depth values in meters, please see the related DEM Global Mosaic (Elevation Values) service.

There are 5 related image services providing access to Digital Elevation Models:

• DEM Mosaic (Individual DEMs)
  
• DEM Global Mosaic (Elevation Values)
  
• DEM Global Mosaic (Color Shaded Relief)
  
• DEM Tiles Mosaic (Newer Tiled DEMs; Elevation Values)
  
• DEM Tiles Mosaic (Newer Tiled DEMs; Color Shaded Relief)
  

NCEI builds and distributes high-resolution, coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to understand and predict changes in Earth's environment, and conserve and manage coastal and marine resources to meet our Nation's economic, social, and environmental needs. They can be used for modeling of coastal processes (tsunami inundation, storm surge, sea-level rise, contaminant dispersal, etc.), ecosystems management and habitat research, coastal and marine spatial planning, and hazard mitigation and community preparedness. For more information about coastal DEMs at NCEI, please see: http://ngdc.noaa.gov/mgg/coastal/coastal.html or learn more from our DEM Fact Sheet (1 MB PDF).

This service is a general-purpose global, seamless bathymetry/topography mosaic. It combines DEMs from a variety of near sea-level vertical datums, such as mean high water (MHW), mean sea level (MSL), and North American Vertical Datum of 1988 (NAVD88). No conversion/harmonization of vertical datums was performed. Because the mosaic contains "overviews" for performance, individual DEMs cannot be separated from the others. Individual DEMs, or smaller subsets, are available in the companion DEM Mosaic (Individual DEMs) image service.

By default, the DEMs are drawn in order of cell size, with higher-resolution grids displayed on top of lower-resolution grids. If overlapping DEMs have the same resolution, the newer one is shown.

The DEMs can be viewed in NCEI's Bathymetric Data Viewer along with other bathymetric datasets stewarded at NCEI.

Please see NCEI's corresponding DEM Footprints map service for polygon footprints and more information about the individual DEMs used to create this composite view. The newer 1/3 and 1/9 arcsecond "tiled" DEMs are hosted by NOAA's Office for Coastal Management; please see the Data Access Viewer for access to these data. View these services together in a single combined map.

In this visualization, the elevations/depths are displayed using this color ramp:


THREDDS catalog (for extracting/downloading DEMs)

This image service provides access to gridded bathymetric products derived from multibeam data collected by the NOAA Ship Okeanos Explorer. The products were created from data collected on cruises starting in 2009 through the current field season. For the companion "seamless mosaic" image service providing depth values and options for visualization, please see Bathy Grids. For daily updates providing initial versions of bathymetric products, please see Near-Real-Time Bathy Grids.Surveys containing restricted data may or may not be included within this layer. Multibeam sonar data and products archived with NOAA National Center for Environmental Information (NCEI) are accessible through the NOAA Ocean Exploration Data Atlas, the Okeanos Explorer Data Landing Pages, and the Bathymetric Data Viewer. Data Visualization Tips:By default, the service provides a color shaded relief visualization of the depth values. Alternatively, the actual depth values in meters can be displayed by setting the processing template to "User Defined Renderer" in the ArcGIS Online layer using the "Image Display" menu, or in ArcMap under "Processing Templates: None".This service has several server-side raster functions available for data visualization. This can be selected in the ArcGIS Online layer using "Image Display", or in ArcMap under "Processing Templates".None (default): Provides depth values in meters.MultidirectionalHillshadeHaxby_8000-0: A color shaded relief visualization using Esri's "multidirectional hillshade". This is also available as a separate tiled service (faster to draw). The depths are displayed using this color ramp:MultidirectionalHillshadeHaxby_DRA: A color shaded relief visualization using Esri's "multidirectional hillshade". The color scale is automatically stretched to the min and max depth values visible in the current view (dynamic range adjustment). The depths are displayed using this color ramp.There are also similar visualizations available using different color ramps (blue, dark blue, purple-blue):Numerous bathymetric AGOL products exist for Okeanos Explorer. Please read the below descriptions to ensure proper usage:Bathy Coverage hosted feature layer provides polygons of where multibeam data were collected. This layer does not visually represent the data values.Bathy Grids imagery layer provides a seamless mosaic of gridded multibeam products. Bathy Grids (subsets) imagery layer is a slightly less optimized version of the previous layer but allows users to filter data based on Survey ID, etc. Near-Real-Time Bathy Grids imagery layer provides a seamless mosaic of provisional multibeam products delivered daily during ship operations. Data not yet archived at NCEI may also be found here prior to ingest.Bathy Grids (tiled color hillshade visualization) layer provides a more optimized data visualization that the previously listed imagery layers. This layer can be coupled with the below tiled elevation layer for 3D visualization within Esri Scenes. Bathy Grids (tiled elevation) layer provides an elevation mesh. Couple this layer with the above tiled color hillshade for 3D visualization within Esri Scenes. Please provide any feedback or questions to OER.info.mgmt@noaa.gov.

Note: this dynamic map service is being replaced with a newer feature layer. Please use this one instead: https://noaa.maps.arcgis.com/home/item.html?id=dbd382c4ef5a4464a0a29dfcefda8d43A map service showing the location and coverage derived from NOAA's National Ocean Service (NOS), Office of Coast Survey (OCS) Hydrographic Surveys in U.S. waters and non-hydrographic surveys acquired external to OCS, that have been assessed by OCS for use in NOAA’s navigational products and the National Bathymetry. The NOS Hydrographic Database (NOSHDB) and Hydrographic Survey Metadata Database (HSMDB), both maintained by NOS and NOAA's National Centers for Environmental Information (NCEI), provide extensive survey coverage and ISO metadata of the coastal waters and Exclusive Economic Zone (EEZ) of the United States and its territories. The NOSHDB contains digitized data from smooth sheets of hydrographic surveys completed between 1837 and 1965, and from survey data acquired digitally on NOS survey vessels since 1965. Data products from NOS surveys and others assessed by NOS, including Bathymetric Attributed Grid (BAG) files, Descriptive Reports, smooth sheet images, survey data images, textual gridded data, and geo-referenced sidescan sonar mosaics, ISO metadata, and survey statistics are available for download from NCEI.Modern surveys provide gridded data in the form of bathymetric attributed grids (BAGs). Please see the following services for mosaics of the BAG data:Bathymetric Attributed Grid (BAG) Image Service (provides depth values).Bathymetric Attributed Grid (BAG) shaded relief visualization image service (color shaded relief).Layers available in this map service:Layer 0: All Surveys with Digital Data: Combining both Surveys with BAGs and Surveys with Digital Sounding Data, this layer describes all bathymetric data collected for NOAA's Office of Coast Survey in a usable digital format as either gridded surface data or xyz point soundings.Layer 1: Surveys with BAGs: This layer includes hydrographic data from ~1995 to the present. A Bathymetric Attributed Grid (BAG) is an open sourced file format for storing and exchanging bathymetric data developed by the Open Navigation Surface Working Group. BAG files are gridded, multi-dimensional bathymetric data files and are the standard NOS hydrographic data file for public release.Layer 2 (hidden by default): Surveys without Digital Data: This layer includes historical hydrographic data from as early as the 1800s. Smooth Sheet images exist for these historical depth soundings that have not been digitized into an xyz format. Smooth Sheets are the final, neatly drafted, accurate plot of verified and corrected bathymetric data based on the method collected and are available as Tagged Image File Format (TIFF), Multi-resolution Seamless Image Database (MrSID) format, or as a geo-referenced PDF.The NCEI Bathymetric Data Viewer (NOAA GeoPlatform entry) can be used to search and display these data. More information about NOS Hydrographic Survey data available at NCEIAlso see the NOS Seabed Descriptions from Hydrographic Surveys Map Service.ISO collection-level metadata for NOS Hydrographic Surveys

A 1/3 arc-second Mean Lower Low Water bathymetric DEM of NOS hydrographic survey data in the Chesapeake Bay Estuary.

The U.S. Interagency Elevation Inventory (USIEI) displays high-accuracy topographic and bathymetric data for the United States and its territories. The project is a collaborative effort between the National Oceanic and Atmospheric Administration, the U.S. Geological Survey, the Federal Emergency Management Agency, the U.S. Department of Agriculture - Natural Resources Conservation Service and U.S. Forest Service, the National Park Service, and the U.S. Army Corps of Engineers. This resource is a comprehensive, nationwide listing of known high-accuracy topographic data, including lidar and IfSAR, and bathymetric data, including NOAA hydrographic surveys, multibeam data, and bathymetric lidar. This zip file contains the attribute information and footprints about the data sets that are displayed in the Topographic Lidar, Topobathy Shoreline Lidar, IfSAR Data, and Bathymetric Lidar layers in the USIEI viewer. This does not include the elevation data itself. The data are provided in Esri file geodatabase format (gdb) and in the open format of OGC GeoPackage (gpkg). The data is also available via this map service: https://coast.noaa.gov/arcgis/rest/services/USInteragencyElevationInventory/USIEIv2/MapServer. The data is updated quarterly. The information provided for each elevation data set includes many attributes such as vertical accuracy, point spacing, and date of collection. A direct link to access the data or information about the contact organization is also available through the inventory. The footprints in this data set are generalized to represent the coverage of the collection. If the exact data coverage is needed, please contact the data provider for an authoritative footprint. The fields in the gdb and gpkg are in four tables. The fields in each table are listed in the Entity Attribute Overview field.

NGDC's U.S. Coastal Relief Model (CRM) provides a comprehensive view of the U.S. coastal zone integrating offshore bathymetry with land topography into a seamless representation of the coast. The CRM spans the U.S. East and West Coasts, the northern coast of the Gulf of Mexico, Puerto Rico, and Hawaii, reaching out to, and in places even beyond, the continental slope. Bathymetric and topographic data sources include: NGDC's NOS hydrographic surveys and multibeam bathymetry; the U.S. Geological Survey (USGS); and other federal government agencies and academic institutions. Bathymetric contours from the International Bathymetric Chart of the Caribbean Sea and the Gulf of Mexico project were also used. Digital elevation models (DEMs) of the Great Lakes, Southern Alaska, and high-resolution DEMs of U.S. coastal communities and territories are also available.

Originally designed for military use, the multibeam echosounder has proved very useful for nautical charting, oceanographic research and modeling, habitat classification, maritime commerce, and recreational applications. The Multibeam Bathymetry Database at NCEI collects and archives multibeam data from the earliest commercial installations (circa 1980) through today's modern high-resolution collections. Data are acquired from a variety of primarily government and academic sources (see individual cruise metadata records for source information) and consist of the raw (as collected) sonar data files. Datasets may also include processed or edited versions of the sonar data, ancillary data, derived products, and/or metadata for the data collection. The Multibeam Bathymetry Database provides data that span the globe and are discoverable and accesible via map interface or text-only search options.

A 1/3 arc-second Mean Lower Low Water bathymetric DEM of NOS hydrographic survey data in Indian River, FL.

A 1/3 arc-second Mean Lower Low Water bathymetric DEM of NOS hydrographic survey data in Galveston Bay.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetric and sidescan-sonar data, originally collected by NOAA for charting purposes, provide a fundamental framework for research and management activities along this part of Block Island Sound, show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. During June 2012, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Interpretations were derived from the multibeam-echosounder, sidescan-sonar, sedimentary, and photographic data collected in Block Island Sound. For more information on the ground-truth survey see http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2012-002-FA.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities along this part of Rhode Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. Interpretations were derived from the multibeam echo-sounder data collected in Rhode Island Sound. During June 2011, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of these areas. For more information on the ground-truth survey see http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2011-006-FA.

Note: this tile layer is no longer being updated. Please use the dynamic map service.Bathymetry is the measurement of the depth of the ocean floor, data that can be used for a variety of purposes such as: nautical charting, oceanographic research and modeling, habitat classification, maritime commerce, and recreational applications. The Multibeam Bathymetry Database (MBBDB) at NCEI collects and archives multibeam data from the earliest commercial installations (circa 1980) through today's modern high-resolution collections. Data are acquired from both U.S. and international government and academic sources (see individual cruise metadata records for source information) and consist of the raw (as collected) sonar data files. Datasets may also include processed or edited versions of the sonar data, ancillary data (i.e., sound velocity data), derived products (i.e., grids), and/or metadata for the data collection. The MBBDB provides data that span the globe and are discoverable and accessible via map interface or text-only search options. More information about the database can be found here. This map service shows ship tracks for multibeam bathymetric surveys archived at NCEI. Attributes are available such as platform name, survey start/end dates, source organization, and links to metadata and data download pages.Note: This is a tile layer, visible from global scales to zoom level 10 (approx. 1:577,000 scale). The corresponding dynamic map service draws at all scales, and allows filtering.NCEI's Bathymetric Data Viewer (NOAA GeoPlatform entry) provides an interactive mapping interface to the multibeam database as well as other sources of bathymetric data.In addition to this service showing the ship tracks, there are also three image services providing access to the gridded multibeam data:Multibeam Bathymetry Mosaic (REST endpoint): provides depth values (default) or shaded-relief imagery. All surveys are combined together (using mean depth value) into "overviews".Multibeam Bathymetry Mosaic: Shaded Relief Visualization: tiled image service, provides rapid display of color shaded relief imagery.Multibeam Bathymetry Mosaic Subsets (REST endpoint): provides access to the individual surveys, and allows filtering by survey ID, platform name, source organization, survey date, etc. This service has slower performance than the others.Metadata for the Multibeam Bathymetric Database

This dataset contains a unified ESRI Geotiff with 1x1 meter cell size representing the bathymetry of El Seco, a selected portion of seafloor east of Vieques Island, derived from data collected in March and April 2009. NOAA's NOS/NCCOS/CCMA Biogeography Branch, in collaboration with NOAA vessel Nancy Foster and territory, federal, and private sector partners, acquired multibeam bathymetry data a...

The National Ocean Service (NOS) Estuarine Bathymetric Digital Elevation Models are gridded bathymetry datasets interpolated from 150 years’ worth of hydrographic survey data collected by the former NOS Special Projects Office. The initiative produced datasets for 70 estuaries in the conterminous United States with sufficient data coverage to support detailed bathymetric processing. Contact dem.info@noaa.gov Use Cases Bathymetric data adds another dimension to geographic mapping and modeling, and can be used as either a background layer or 3D surface for draping thematic maps such as benthic or marine organism habitats and geologic data. It also delineates the lower boundary of the water column in hydrodynamic models used to monitor and predict the movement of oil and hazardous materials, temperature and salinity distributions, animal migration patterns, and model storm surge and tsunami effects. Data Characteristics The perimeter of each bathymetry aligns with estuarine drainage

This data set is part of a larger set of data called the Multibeam Bathymetry Database (MBBDB) where other similar data can be found at https://maps.ngdc.noaa.gov/viewers/bathymetry/NOAA's National Centers for Environmental Information (NCEI) is the U.S. national archive for multibeam bathymetric data and presently holds over 2400 surveys received from sources worldwide, including the U.S. academic fleet via the Rolling Deck to Repository (R2R) program. In addition to deep-water data, the multibeam database also includes hydrographic multibeam survey data from the National Ocean Service (NOS). This map service shows navigation for multibeam bathymetric surveys in NCEI's archive. Older surveys are colored orange, and more recent recent surveys are green.

A 1/3 arc-second Mean Lower Low Water bathymetric DEM of NOS hydrographic survey data in Chesapeake Bay.A map service showing the location and coverage of land and seafloor digital elevation models (DEMs) available from NOAA's National Centers for Environmental Information (NCEI). NCEI builds and distributes high-resolution, coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to understand and predict changes in Earth's environment, and conserve and manage coastal and marine resources to meet our Nation's economic, social, and environmental needs. They can be used for modeling of coastal processes (tsunami inundation, storm surge, sea-level rise, contaminant dispersal, etc.), ecosystems management and habitat research, coastal and marine spatial planning, and hazard mitigation and community preparedness. Layers available in the map service: Layers 1-4: DEMs by Category (includes various DEMs, both hosted at NCEI, and elsewhere on the web); Layers 6-11: NCEI DEM Projects (DEMs hosted at NCEI, color-coded by project); Layer 12: All NCEI Bathymetry DEMs (All bathymetry or bathy-topo DEMs hosted at NCEI).This is an ArcGIS image service showing color shaded relief visualizations of high-resolution digital elevation models (DEMs) of U.S. coastal regions. NOAA's National Geophysical Data Center (NGDC) builds and distributes high-resolution coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to understand and predict changes in Earth's environment, and conserve and manage coastal and marine resources to meet our Nation's economic, social, and environmental needs. They can be used for modeling of coastal processes (tsunami inundation, storm surge, sea-level rise, contaminant dispersal, etc.), ecosystems management and habitat research, coastal and marine spatial planning, and hazard mitigation and community preparedness. DEMs included in this visualization: High-resolution DEMs of select U.S. coastal communities and surrounding areas. Most are at a resolution of 1/3 to 1 arc-second (approx 10-30 m); U.S. Coastal Relief Model: A 3 arc-second (approx 90 m) comprehensive view of the conterminous U.S. coastal zone, Puerto Rico, and Hawaii; Southern Alaska Coastal Relief Model: A 24 arc-second (approx. 500 m) model of Southern Alaska, spanning the Bering Sea, Aleutian Islands, and Gulf of Alaska. This map service can be used as a basemap. It has a transparent background, so it can also be shown as a layer on top of a different basemap. Please see NGDC's corresponding DEM Footprints map service for polygon footprints and more information about the individual DEMs used to create this composite view.

The U.S. Geological Survey (USGS), in cooperation with the Connecticut Department of Environmental Protection and National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities along this part of Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. Interpretive data layers were derived from the multibeam echo-sounder data collected north of Duck Pond Point, New York. During April and May 2010, bottom photographs and surficial sediment data were acquired during 2 cruises as part of USGS ground-truth reconnaissance surveys of this area. For more information on the ground-truth surveys see http://quashnet.er.usgs.gov/data/2010/10010/ and http://quashnet.er.usgs.gov/data/2010/10015/.