Recent years have seen remarkable advances in sonar technology, positioning capabilities, and computer processing power that have revolutionized the way we image the seafloor. The massive amounts of data produced by these systems present many challenges but also offer tremendous opportunities in terms of visualization and analysis. We have developed a suite of interactive 3-D visualization and exploration tools specifically designed to facilitate the interpretation and analysis of very large (10's to 100's of megabytes), complex, multi-component spatial data sets. If properly georeferenced and treated, these complex data sets can be presented in a natural and intuitive manner that allows the integration of multiple components each at their inherent level of resolution and without compromising the quantitative nature of the data. Artificial sun-illumination, shading, and 3-D rendering can be used with digital bathymetric data (DTM's) to form natural looking and easily interpretable, yet quantitative, landscapes. Color can be used to represent depth or other parameters (like backscatter or sediment properties) which can be draped over the DTM, or high resolution imagery can be texture mapped on bathymetric data. When combined with interactive analytical tools, this environment has facilitated the use of multibeam sonar and other data sets in a range of geologic, environmental, fisheries, and engineering applications.

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Recent oil and gas exploration efforts have met with success in the deepwater environment along the Sigsbee Escarpment in the north-central Gulf of Mexico. The topography of the Sigsbee is steep and irregular with numerous faults and slumps occurring on the Escarpment face. The complex topography is challenging for the collection of high-resolution geophysical data. Engineering quality survey data for the installation of export pipelines, infield flowlines and production facilities is needed. BP Exploration and Production Inc. (BP) recognized the limitations of the current survey technology and put forth a push in the industry for the development of a deepwater, Autonomous Underwater Vehicle (AUV) survey platform. A commitment for state-of-the-art survey technology by BP resulted in C & C Technologies, Inc. (C & C) teaming with Kongsberg Simrad to develop an AUV platform for the deployment of high-resolution survey instrumentation capable of surveying to a maximum depth of 3,000 meters. An overview of the system, data processing and data examples from missions completed across the Sigsbee Escarpment are presented in this paper.The data from the AUV has provided a dramatic advance in the ability to map the seafloor, but it produces a large and diverse data set that can challenge our ability to process and manage the data. The great density of these digital data, however, offers the opportunity to take advantage of interactive 3D visualization techniques that can improve the efficiency and accuracy of processing, and provide an unprecedented perspective of seafloor morphology and processes. Fledermaus interactive 3D visualization software is used to aid in the analysis of the data. This program allows the interpreter to analyse in a single scene all the data from AUV survey, including the seabed from the multibeam sonar, draped side scan, subbottom profiles and the planned pipe routes.

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A regional multibeam bathymetric and imagery survey of the Canadian Scotian Margin was performed by C & C Technologies, Inc. The survey was spearheaded by the Geological Survey of Canada (Atlantic), which acted as a partner with an industry group consisting of Marathon Canada, Norsk Hydro Canada, PanCanadian, and Murphy Oil. The survey is providing one component for use in hazard assessment within the lease block area of the central Scotian Slope, and forming an integral part of regional research carried out by the Geological Survey of Canada Atlantic (GSCA) funded by PERD and industry partners. The multibeam imagery is being used to derive a regional assessment of the character of seabed morphology, erosion, and the distribution of slope instabilities throughout the Scotian Slope. Spatial resolution is higher than in 3-D seismic data, especially on the mid to upper Slope, and the 17,000 km2 survey area provides regional coverage. Many of the large features (canyons and slope instabilities) on the Scotian Slope extend for many kilometers, and therefore their interpretation requires regional information. In particular, the multibeam imagery allows precise targeting of seabed features for subsequent higher resolution surveys of small critical areas and seabed sampling. Side scan sonar, sub-bottom profiling, and ROV surveys can provide fine detail of critical features. Precisely located samples can be used to obtain measurements of sediment properties, age dating of sediments, and benthic biota. A 30-day sampling cruise was performed by GSCA on the CCGS "Hudson", which acquired high-resolution seismic profiles and piston and box cores in targeted features. The targeted data will be used to ground truth the multibeam imagery and to assess geologic conditions and hazards of the Scotian Slope. The bathymetry data are being evaluated with new technology developed by the University of New Brunswick, Canada, which interactively integrates them into one common graphical environment and allows for precise identification of geologic correlations. Introduction Many exploration and production companies are showing interest in the Scotian Slope off eastern Canada. More than 3,000,000 ha. have been leased since 1999 (Fig. 1). In spring of 2000, C&C Technologies acquired more than 16,500 km2 of multibeam bathymetry (Fig. 2) and backscatter data from the central part of the Scotian Slope using an EM300 system. The survey covered 15 lease blocks and extended from about 700 m to 3000 m water depth. In addition, a separate survey by Clearwater Fine Foods Inc. and the Geological Survey of Canada acquired multibeam bathymetry from 700 m to 150 m water depth on the upper slope using an EM1002 system. The purpose of the survey was to provide the GSC(A) and industry partners with regional information on surficial hazards, including sediment slides, surface faulting, and pockmarks, and on the distribution of near surface sediments that influence benthic habitat. Following the acquisition of the multibeam data, the Geological Survey of Canada, with supplementary funding from the industry partners, carried out two 15-day confirmation cruises.