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12 st / September 2015 www.sea-technology.com Altogether, the shoreline videos, georeferenced photos, aerial photog- raphy, historical satellite imagery, and the geospatial software utilized for vi- sualization became known to OSI as the "Ancillary Data Toolbox." High-Water Feature Designation In MBES Data The abundant submerged features identifed with SSS and MBES sonar were processed, correlated and report- ed using standard and custom methods within CARIS HIPS and SIPS. In order to better isolate and manage high-wa- ter features, a nonstandard approach was employed to handle soundings on items such as piers, foating docks and vessels on and above the surface. For the fnal data set, the "Exam- ined" sounding fag was used to in- dicate high-water features, establish- ing the distinction between surface features, the seafoor bathymetry and submerged obstructions and wreck- age. Distinguishing the high-water fea- tures with sounding classifcation tools assisted data analysts in linking what was surveyed below the water line to what was documented above the wa- ter line in the videos, photographs and aerial imagery. Along piers and foating docks, often times, wrecks, obstruc- tions and ruined or submerged pilings were surveyed at the base of intact support pilings or beneath moored ves- sels. Retaining the high-water features in the sounding point cloud enhanced the perspective of features above and below water and their position relative to each other. This was particularly im- portant for features that were awash, partially submerged, or covered and uncovered at different tidal stages. Feature Correlation and Classifcation A primary data processing chal- lenge for the Jamaica Bay survey area was proper identifcation and attribu- tion of densely spaced, haphazardly situated shallow-water features. Within the survey area, OSI was assigned 402 charted features that required verifca- tion, updating or disproval. Along with verifcation of source features, all new shoreline and bathymetric features were to be reported. Sonar contacts from the two 100-percent SSS coverage data sets were distilled down from 12,000 in- dividual contacts to approximately 6,000 contact groups, i.e., correlated contacts. Having begun the feature correlation with 402 source features to verify, the fnal feature count of noteworthy marine debris or objects of navigational signifcance for the Ja- maica Bay survey area was 3,157 fea- tures, with 241 of those being charted features recommended for deletion. Feature least depths were obtained from the multibeam data whenever possible, and all relevant attribution for obstructions, wrecks, pilings and shoreline constructions, including "water level" (e.g., submerged, awash, covered/uncovered, always dry), were determined utilizing all the available tools: MBES, SSS, video, photography, and aerial imagery. The Ancillary Data Toolbox was in- dispensable in properly identifying and classifying navigational hazards; hav- ing a link between the bathymetry and the surface conditions was essential in this task. Take, for example, the disproval of a charted dock with MBES and SSS sur- vey data. In the ruined dock's charted location remained pilings, both drying and submerged, and multiple foating, drying and submerged wrecks. On the surface, captured with the GoPro video, was a foating wreck still tied to a support piling, while multiple unte- thered derelict vessels foated against the nearby Z-sheet bulkhead. Beneath the surface in the MBES data point cloud, a submerged piling and a wreck with its stern in the bottom were vis- ible, both having long acoustic shad- ows that might indicate high-water features. By utilizing the GoPro video, SSS data and satellite imagery, the OSI hydrographers were able to confrm these features were submerged. The Examined sounding fags were then as- signed to isolate the submerged pilings from the intact pilings and the foating wrecks from the drying and submerged wrecks. In addition, there were many in- stances where large obstructions and wrecks were surveyed beneath docks and piers that were still in service. In areas where new construction re- placed destroyed docks, remnants of the pier ruins and/or submerged pil- ings were often located in the imme- diate vicinity. By correlating the MBES data, SSS data and the classifed high- water soundings with the imagery, photos and videos that constituted the Ancillary Data Toolbox, hydrographers could confdently interpret the densely