1. Center for Coastal & Ocean Mapping/Joint Hydrographic Center, University of New Hampshire, Durham, NH 03857, USA
2. Office of Coast Survey, National Oceanic and Atmospheric Administration, Silver Spring, MD 20910, USA
3. Cartography Laboratory, National Technical University of Athens, 15780 Athens, Greece
4. Instituto Hidrografico de la Marina, Spanish Navy, 11007 Cadiz, Spain