The dynamics present in ocean/surf-zone/beach interface creates unique challenges to the hydrographic surveyor.  OSI hydrographers use offshore survey vessels (e.g. single beam), sea-sled surf zone topography, and topographic land surveying techniques to produce seamless beach profiles.  Beginning behind the dune, these profiles continue down the beach face and through the surf to a point a mile offshore.  OSI uses RTK GPS for positioning to ensure that tidal zoning assumptions do not impact vertical accuracy.  Quality assurance checks are strictly observed (including substantial method overlap) ensuring full-length profile accuracy.