Bogue Sound, NC (S030) Bathymetric Digital Elevation Model(30 meter resolution) Derived From Source Hydrographic SurveySoundings Collected by NOAA

Bathymetry for Bogue Sound was derived from eleven surveys containing52,366 soundings. Two older, overlapping, less accurate surveys wereentirely omitted. The overlap from one older, less accurate surveywas omitted before tinning the data. The average separation betweensoundings was 72 meters. Surveys dating from 1876 to 1953 coveredthe east and west portions of the sound. Surveys from 1974 coveredthe center portion of the sound. The total range of sounding datawas 0.9 to -17.1 meters at mean low water. Mean high water valuesbetween 0.5 to 1.0 meters were assigned to the shoreline. Onepoint that was not consistent with the surrounding data was removedprior to tinning. DEM grid values outside the shoreline (on land)were assigned null values (-32676).Bogue Sound has six 7.5 minute DEMs and two one degree DEMs. The 1degree DEMs were generated from the higher resolution 7.5 minute DEMswhich covered the estuary. A Digital Elevation Model (DEM) contains aseries of elevations ordered from south to north with the order ofthe columns from west to east. The DEM is formatted as one ASCIIheader record (A- record), followed by a series of profile records(B- records) each of which include a short B-record header followedby a series of ASCII integer elevations (typically in units of 1centimeter) per each profile. The last physical record of the DEM isan accuracy record (C-record).The 7.5-minute DEM (30- by 30-m data spacing) is cast on theUniversal Transverse Mercator (UTM) projection. It provides coveragein 7.5- by 7.5-minute blocks. Each product provides the samecoverage as a standard USGS 7.5-minute quadrangle but the DEMcontains over edge data. Coverage is available for many estuaries ofthe contiguous United States but is not complete.