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(2) The processing and editing steps on board the ship were:
(A.) Demultiplex, or unravel, the acquired Simrad data files using RT to generate separate files containing navigation, depth soundings, sidescan sonar backscatter values, and sound velocity information.
(B.) Automatically reject bad data (autoRejectSoundings). For the multibeam soundings, reject data outside expected depth ranges (operator's decision based on nautical chart data); for navigation data, reject fixes with poor GPS statistics.
(C.) Edit the navigation data on-screen using jview to remove undesirable points, including turns at the ends of survey lines.
(D.) Edit the multibeam soundings on-screen using swathed to remove individual anomalous soundings.
(E). Merge tidal information and the corrected navigation back (mergetide and mergenav) into the data files. Tidal information was obtained from predicted tides using the Xtide program <http://www.flaterco.com/xtide/xtide.html>), which generated predicted tides based on the harmonic coefficients for Chatham provided by the Xtide program.
(F.) Map the bathymetric soundings from each processed data file onto a Mercator grid using weigh_grid (a SwathEd utility) with node spacings and scale selected by the operator. The grid file (capenorth.r4) was a floating point binary file.
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