Utilization of LIDAR and NOAA´s Vertical Datum Transformation Tool (VDatum) for Shoreline Delineation

The National Oceanic and Atmospheric Administration (NOAA), an organization of the U.S. Department of Commerce, is mandated to map the United States´ coastal boundary, defining the nation´s legal shoreline. This paper presents a new methodology for extraction of shorelines from lidar data. The methodology incorporates NOAA´s vertical datum transformation tool (VDatum) for transforming lidar data to a specified tidally-based datum for shoreline extraction. The VDatum utility comprises geoid models, fields representing departures of an orthometric datum from local mean sea level, and hydrodynamic models portraying tidal regimes for accurate demarcation of coastal lines. The procedure presented here minimizes the variability and subjectivity that have plagued more traditional shoreline delineation techniques. The semi-automated routine allows for consistent, non-interpreted shorelines to be derived, providing significant advantages over proxies such as the high water line, beach scarps, and dune lines. This technique is invariant to coastline type, and has provided good results for a range of margins, such as a sandy or rocky. Additional advantages include the ability to derive multiple tidally-based shorelines from a single dataset and greater flexibility in data acquisition. Perhaps most importantly, the lidar data can be collected in a manner to support a variety of Integrated Ocean and Coastal Mapping (10CM) applications, including nautical charting, storm surge/tsunami modeling, coral reef mapping, ecosystem monitoring, and coastal mapping.