BlueTopo is a compilation of the nation's best available bathymetric data. Created as part of the NOAA Office of Coast Survey's nautical charting mission and its National Bathymetric Source (NBS) program, BlueTopo is curated bathymetric source data to provide a definitive nationwide model of the seafloor and navigational lakes. In the same way that a topographic map details the height of land, BlueTopo details the depth of lake beds and seafloor beneath navigationally significant U.S. waters. Primary sources of bathymetry in NBS compilations 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. Coverage gaps in water over 200 meters are filled in BlueTopo through Global Multi-Resolution Topography, a merged model of bathymetry made available through Lamont-Doherty Earth Observatory. In addition to compiled bathymetry, BlueTopo contains metadata with quality metrics from the source data to enable the appropriate use of the product.

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.

BlueTopo Bathymetry Dataset - Northeast US Continental Shelf. 4m-resolution bathymetric data compiled from NOAA BlueTopo tiles. cdm_data_type=Grid Conventions=CF-1.10, COARDS, ACDD-1.3 Easternmost_Easting=-65.94198732413663 GDAL=GDAL 3.11.3 "Eganville", released 2025/07/12 GDAL_AREA_OR_POINT=Area GDAL_TIFFTAG_ARTIST=NOAA Office of Coast Survey GDAL_TIFFTAG_COPYRIGHT=https://creativecommons.org/publicdomain/zero/1.0/ GDAL_TIFFTAG_DATETIME=* GDAL_TIFFTAG_IMAGEDESCRIPTION=* GDAL_VERTICALDATUMWKT=* geospatial_lat_max=45.07659731796417 geospatial_lat_min=37.17543731796417 geospatial_lat_resolution=3.0000000000000018E-5 geospatial_lat_units=degrees_north geospatial_lon_max=-65.94198732413663 geospatial_lon_min=-74.41014732413663 geospatial_lon_resolution=2.999999999999999E-5 geospatial_lon_units=degrees_east grid_mapping_crs_wkt=GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AXIS["Latitude",NORTH],AXIS["Longitude",EAST],AUTHORITY["EPSG","4326"]] grid_mapping_GeoTransform=-74.410162324136635 3.0000000000000001e-05 0 45.07661231796417 0 -3.0000000000000001e-05 grid_mapping_inverse_flattening=298.257223563 grid_mapping_long_name=CRS definition grid_mapping_longitude_of_prime_meridian=0.0 grid_mapping_name=latitude_longitude grid_mapping_semi_major_axis=6378137.0 grid_mapping_spatial_ref=GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AXIS["Latitude",NORTH],AXIS["Longitude",EAST],AUTHORITY["EPSG","4326"]] history=NOAA BlueTopo tiles merged and reprojected infoUrl=https://www.nauticalcharts.noaa.gov/data/bluetopo.html institution=NOAA keywords_vocabulary=GCMD Science Keywords Northernmost_Northing=45.07659731796417 sourceUrl=(local files) Southernmost_Northing=37.17543731796417 standard_name_vocabulary=CF Standard Name Table v70 Westernmost_Easting=-74.41014732413663

NOAA’s BlueTopo bathymetry was used to delineate Jordan Basin, Parker ridge, Three Dory ridge, and Davis Swell. Excerpt from the U.S. Office of Coast Survey: "BlueTopo is a compilation of the nation's best available bathymetric data. In the same way that topographic map details the height of land, BlueTopo details the depth of lake beds and seafloor beneath navigationally significant U.S. waters. Created as part of the Office of Coast Survey nautical charting mission and its National Bathymetric Source project, BlueTopo is curated bathymetric source data to provide a definitive nationwide model of the seafloor and navigational lakes."Derived data source: NOAA’s BlueTopo bathymetry