NGA's Analysis of the Smith and Sandwell Bathymetry Model (topo_8.2) and Implications for Bathymetric Modeling

NGA reviews its analysis of the bathymetry model developed by Walter H. F. Smith, NOAA, and David T. Sandwell, Scripps Institution of Oceanography. The Smith and Sandwell file was computed from altimetry, soundings, and other sources. The analysis makes use of NGA's best soundings as truth data and their elevation/depth file computed without altimetry. The purpose of this analysis is to determine the status of bathymetric modeling using various sources, opportunities for improving bathymetric modeling, and the possibilities of incorporating other sources such as gravity anomalies and LIDAR data into the solution. NGA is considering the use of such multiple source bathymetry models as a means to provide a "cautionary" overlay to bathymetric charts to support route planning