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NOS Interactive Map Screen Shot

NOS survey descriptive report image
Descriptive report

NOS sidescan sonar mosaic image
Sidescan sonar mosaic

NOS Survey H12373 new geoPDF smooth sheet
Survey H12373
geo-referenced PDF
smooth sheet


1950s NOS Smooth sheet image
1950s smooth sheet

NOS Hydrographic Survey Data

NOS Shallow Water Multibeam 3d image
Survey H12112
San Francisco Bay 3D image

NCEI maintains the National Ocean Service Hydrographic Data Base (NOSHDB) and Hydrographic Survey Meta Data Base (HSMDB). Both are populated by the Office of Coast Survey and National Geodetic Service, and provide coverage of coastal waters and the U.S. exclusive economic zone and its territories.

NOSHDB: Over 76 million soundings from more than 6,600 surveys: hydrographic survey smooth sheets between 1837 and 1965, and from NOAA survey vessels since 1965.

HSMDB: ISO metadata records, text search, and display of NOAA data and products. Metadata for historical foreign surveys is limited or non-existent.

Rap Sheets: Displays survey summaries and locations, cross references, statistics, comprehensive platforms and correctors, processing and archive information. Survey types: Hydrographic, Field Edit, Reconnaissance, Lake, and Non-NOS sources.

Data Products: BAG files, Descriptive Reports, smooth sheet images, survey data images, textual gridded data, and geo-referenced sidescan sonar mosaics, FGDC/RSE metadata, and survey statistics.

  • Bathymetric Attributed Grid (BAG) is a non-proprietary 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. Current versions of the BAG file contain position and depth grid data, as well as position and uncertainty grid data, and the metadata specific to that BAG file, providing end users information about the source and contents of the BAG file. Please visit the Open Navigation Surface Working Group for additional information on BAG files.

    NCEI developed the capability to output data from BAG files as American Standard Code for Information Interchange (ASCII) xyz files. Empty space in BAG files is not included in xyz output files. Individual files, or entire surveys spanning multiple BAG files, can be selected, extracted, processed to xyz format, and zipped for shipment using the new conversion capability. Each conversion also creates an Extensible Markup Language (XML) metadata file.

  • Geospatial Portable Document Format (GeoImage) is a layered geospatial PDF. This image file contains: a combined bathymetric surface, a survey scale set of soundings, a large scale raster nautical chart, latitude/longitude graticule, title block, and an acoustic imagery mosaic (if available). The image is geographically referenced to locate features, measure distances and angles, and select specific layers of interest. A stand-alone ASCII XYZ file of the sounding set and additional survey metadata are attached to the PDF.

  • Descriptive Reports (DRs) are approved metadata documents relevant to survey level hydrographic data and are available in PDF or Extensible Markup Language (XML). The DR is a narrative document that describes the conditions under which the hydrographers performed the work and discusses various factors affecting the adequacy and accuracy of the results.

  • Smooth Sheets are the final, neatly drafted, accurate plot of verified and corrected data based on the method collected, available as Tagged Image File Format (TIFF), Multi-resolution Seamless Image Database (MrSID) format, or as a geo-referenced pdf.

    NCEI archives and disseminates over 11,000 smooth sheets and 8,000 DRs from the mid-1800s to the present. The survey data images, gridded data, and sidescan sonar mosaics are available only for recent surveys where NOS collected high-resolution data.

  • Seabed descriptions are available for some surveys. These brief descriptions of bottom type encountered during the survey use the International Hydrographic Organization IHO S-57 descriptive attributes as described in the NOAA Office of the Coast Survey NOS Hydrographic Survey, Specifications and Deliverables (2014 PDF).