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www.sea-technology.com October 2014 / st 27 data, and to address the many emerging uses and users for the data. For some appli- cations, the variation of these data through time is also important, and this demands an addition of a tempo- ral framework to the geospatial processing environment. Another challenge is the variety of acquisition formats and the large data vol- ume associated with water column data. Initial Development, Feature Extraction The initial develop- ment of FMMidwater at QPS (Portsmouth, New Hampshire) more than four years ago was built on research from the Center for Coastal and Ocean Mapping, University of New Hampshire (CCOM UNH), to investigate methods for interactively visualizing time- varying geospatial data. The water column data required a number of new visualization metaphors to be added to the standard approach to bathymetric and seabed backscat- ter data. The metaphors needed to address the geospatial and temporal aspects of the analysis, as well as extract fully refracted and adjusted detections to fuse with seabed de- tections from the multibeam processing and visualization. Initially, the tool used the fan and vertical curtain for dis- playing the multibeam water column data. This was then extended to include a stacked curtain, extracted points and volume objects. All objects have a temporal component to allow exploration in both space and time. The FMMidwater tool allows users to extract the water column data for visu- S ince the introduc- tion of hydrographic multibeam sonar, map- ping and charting of the seafoor has evolved throughout the last few decades. The initial fo- cus of these sonar sys- tems was the charting of depths in support of safe- ty of navigation and off- shore exploration; more recently, this has extend- ed to the development of approaches to character- ize seafoor type and for mapping seafoor habi- tat and geohazards. The software tools to process and analyze the bathym- etry, and more recently to characterize the sea- bed from the backscatter, are available in commer- cial software and support the majority of modern sonar systems. The latest generation of hydrographic multibeam sonar now has the ability to map the water column along with the seafoor. Utilization of water column data has the potential to address a number of research areas, including detecting complex hard targets (wrecks, etc.) above the seabed, map- ping fsh and marine mammals and a wide range of physi- cal oceanographic processes. However, users have a limited view of midwater data in real time, and until recently, they mostly relied on their own in-house software tools to study the water column data. The variety of applications for wa- ter column data is one of the complications for developing commercial tools to process and analyze the data. It is es- sential to ensure that fexibility is incorporated in the com- mercial tool to allow for both the simple addition of evolving data types as more multibeam sonar provide water column New Tools for Water Column Feature Detection, Extraction and Analysis FMMidwater Interactively Visualizes Time-Varying Geospatial Data By Lindsay Gee • Lindsay McKenna • Jonathan Beaudoin Overview of Gulf of Mexico showing coverage from NOAA Ship Okeanos Explorer expedition EX1402 March to April 2014.