| Albemarle Sound, NC (S010) Bathymetric Digital Elevation Model (30 meter resolution)
Derived From Source Hydrographic Survey Soundings Collected by NOAA |
| Bathymetry for Albemarle Sound was derived from twenty-five surveys containing 187,065
soundings. Two older, less accurate, overlapping surveys were omitted before tinning.
The average separation between soundings was 115 meters. There was one survey in the
west that dated from 1874. The remaining twenty-four surveys used dated from 1917
to 1942. The total range of sounding data was 0.7 meters to - 14.3 meters at mean
low water. A mean high water value of 0.2 meters was assigned to the shoreline. Eight
points were found that were not consistent with the surrounding data. These were removed
prior to tinning. DEM grid values outside the shoreline (on land) were assigned null
values (-32676). Albemarle Sound has forty-nine 7.5 minute DEMs and four one degree
DEMs. The 1 degree DEMs were generated from the higher resolution 7.5 minute DEMs
which covered the estuary. A Digital Elevation Model (DEM) contains a series of elevations
ordered from south to north with the order of the columns from west to east. The DEM
is formatted as one ASCII header record (A- record), followed by a series of profile
records (B- records) each of which include a short B-record header followed by a series
of ASCII integer elevations (typically in units of 1 centimeter) per each profile.
The last physical record of the DEM is an accuracy record (C-record). The 7.5-minute
DEM (30- by 30-m data spacing) is cast on the Universal Transverse Mercator (UTM)
projection. It provides coverage in 7.5- by 7.5-minute blocks. Each product provides
the same coverage as a standard USGS 7.5-minute quadrangle but the DEM contains over
edge data. Coverage is available for many estuaries of the contiguous United States
but is not complete. |
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