These Multibeam Summary Products are generated by the Okeanos Explorer's Mapping Data Team at the Center for Coastal and Ocean Mapping Joint Hydrographic Center (CCOM/JHC) at the University of New Hampshire (UNH).
 
These products are produced after each NOAA Ship Okeanos Explorer mission.

The bathymetry data were generated using a Kongsberg EM302 multibeam system, and recorded using Kongsberg's Seafloor Information System (SIS) software as *.all files. Collocated to the bathymetric data, bottom backscatter data were collected stored within *.all files, both as beam averaged backscatter values, and as full time series values within each beam. Realtime corrections to the data include: continuous application of surface sound speed obtained with a hull-mounted SBE 45 thermosalinograph, application of sound speed profiles obtained with Sippican Deep Blue Expendable Bathythermographs (XBTs) and / or Seabird CTD 9/11, application of roll, pitch, and heave motion corrections obtained with POS M/V V.4 motion sensor unit. Each raw multibeam file was imported into CARIS HIPS and SIPS 8.1. Each file was individually cleaned of errant depth values using CARIS's Swath Editor. The files were then added to a cumulative gridded Base Surface within CARIS, and further cleaned of errant depth values using CARIS's Subset Editor, taking advantage of available overlapping swaths. Motion corrector values from POS M/V V. 4 applied in real-time were verified in CARIS's Attitude and Navigation editors. No tidal corrections were applied. The ASCII XYZ file was then imported into QPS Fledermaus v.7 to build an *.sd file. The *.sd file retains the resolution of the source gridded ASCII XYZ data. The *.sd file format was selected for its ability to be viewed using the Fledermaus iView4D freeware distributed by QPS.

Multibeam data was processed into Fledermaus scene files used in planing remotely-operated vehicle dives. A scene file is a combination of SD files saved into a single file, which when opened opens all the SD files in one scene . Scene files with up to four layers are viewable in Fledermaus freeware, iView4D. To create these multi-layer Fledermaus scene files, a number of additional field processing steps were performed on a subset of the multibeam files. Bathymetric SD files were run through the "Compute Slope" function in Fledermaus to generate seafloor slope maps. Fledermaus Geocoder Tool v7.3 was used to create bottom backscatter mosaic SD files. The mosaics were then draped over the bathymetric SD files using the "Attach Scalar to Surface" function in Fledermaus. ROV Dive Track points were placed on the seafloor in Fledermaus using the Geo-Picking tool, and were saved as a points layer in the scene file. Selected water column files were processed using Fledermaus FMMW, and anomalies, in particular suspected seep locations, were exported so Fledermaus SD files. These data layers were opened simultaneously in Fledermaus, then saved as a scene file with up to four layers.

Please do not hesitate to contact the Okeanos Mapping team (oar.oer.exmappingteam@noaa.gov) with any questions regarding these files. 

If you are interested in downloading the raw data (level-0) or cleaned/edited data (level-1), you can access those data from the NOAA National Data Center for geophysical data.  http://www.ngdc.noaa.gov/mgg/bathymetry/multibeam.html

For questions or assistance, OER’s Data Management Team can be reached at oer.info.mgmt@noaa.gov