| Cape Fear River, NC (S050) Bathymetric Digital Elevation Model (30 meter resolution)
Derived From Source Hydrographic Survey Soundings Collected by NOAA |
| Bathymetry for the Cape Fear River was derived from seven surveys containing 34,390
soundings. No surveys were omitted. The average separation between soundings was 54
meters. One survey in the south dated from 1934. The remaining six surveys dated from
1970 to 1975. The total range of sounding data was 1.0 meters to -17.3 meters at mean
low water. Mean high water values of 1.2 or 1.3 meters were assigned to the shoreline.
Five 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). The Cape Fear River has seven 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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