WreckSight: revealing our submerged maritime heritage

This paper describes WreckSight, an interactive application for viewing aesthetically considered, accurate, 3D visualisations of historic shipwrecks on the seabed. Maritime heritage sites around the world, especially historic shipwrecks, are typically difficult to access by the general public. In many cases they are beyond the reach of traditional maritime archaeological investigation due to depth and low visibility. Historically significant wrecks have been successfully raised to the surface for research and public exposition in recent years. The Mary Rose raised in 1982 from Portsmouth harbour (UK) and the wreck of the US Civil War submarine Hunley recovered in 2000 from Charleston Bay, are on public display along with many artefacts recovered from the wrecks. However, the majority of historic shipwrecks lie at the site of their sinking, on the seabed, hidden from the public view. Recent improvements in multibeam sonar technologies have resulted in new opportunities to gather very high definition, 3D point cloud data from submerged historic shipwreck sites, therefore offering the potential to create highly accurate 3D images for public exposition. Traditional maritime archaeological methods for displaying this data can be improved by addressing a number of known problems. These are:

· Gaps between points allow data to show through from the other side of the wreck, potentially misrepresenting the structure of the wreck.

· Point cloud data contains no inherent colour information. Traditional display methods apply arbitrary colour ramps to the data which often does not enhance the viewer's interpretation of the wreck.

· Points are rendered at the same size regardless of their distance from the viewer

The WreckSight application resolves these problems by utilising occlusion objects, locally oriented colour ramps (Locoramps) and digital cinematography. This 3D visualisation tool also has applications beyond heritage, e.g. in the marine salvage industry, recreational dive planning and environmental management.