NGDC's digital hydrographic data holdings have been released as a CD/DVD data set by NGDC's Marine Geology and Geophysics Division, complete with PC-compatible search and retrieval software for Microsoft Windows as well as UNIX compatible X-Windows. Data are stored in the HYD93 Data Exchange Format. Each ASCII header file contains 24 80-character records, each containing specific fields. Each ASCII data file contains a series of 37-character data records for a particular hydrographic survey. Records include bathymetric soundings and hydrographic featrures.
Because the database contains all depth values obtained during the surveys, more detailed bathymetric information is available than can normally be found on published nautical charts compiled from the same surveys. The dense inshore and shallow-water data are well suited for computer generation of grids to be used in hydrodynamic models of estuaries and other coastal systems. The data provided are an historical data set, and as such they may not always reflect current conditions. Thus the data are NOT TO BE USED FOR NAVIGATION PURPOSES. For navigation uses, please refer to the NOS Nautical Chart Series. These can be obtained at various chart vendors or by contacting: Customer Services, N/CG333, NOAA, National Ocean Service, 6501 Lafayette Ave., Riverdale, MD 20737-1199.