USGS Center for Coastal and Watershed Studies
NOAA National Ocean Service
U.S. Geological Survey
20121212
North Carolina topographic/bathymetric/LIDAR DEM
SDE raster digital data
http://topotools.cr.usgs.gov/topobathy_viewer/
This data set is a hybrid elevation model created primarily from NOAA bathymetry and USGS LiDAR-based topography. Additional datasets were collected using a variety of technologies, including singlebeam and multi-beam bathymetry, Submetrix Interferometric Sonar Bathymetry, and Shoaling Waves Experiment (SHOWEX) data.
This data set is intended for geospatial applications that require seamless land elevation and water depth information in coastal environments.
As needed
-77.250000
-74.851543
36.746959
34.045015
None
derived surface
DEM
first return elevation
submerged topography
digital elevation model
aerial digital photography
water thickness
elevation
LIDAR
bathymetry
topography
bare earth elevation
benthic cover types
process
mapping
sea surface directional wave spectrum
ISO 19115 Topic Categories
elevation
U.S Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, D. C., NIST
North Carolina
NC
Pamlico Sound
Albemarle Sound
None
North Carolina
Gates County
Camden County
Currituck County
Northampton County
Hertford County
Halifax County
Pasquotank County
Perquimans County
Chowan County
Bertie County
Dare County
Tyrrell County
Martin County
Washington County
Pitt County
Beaufort County
Hyde County
Craven County
Pamlico County
Jones County
Carteret County
Onslow County
USGS Geographic Names Information System
None
NOT TO BE USED FOR NAVIGATION
U.S. Geological Survey
Dean Gesch
mailing and physical
EROS Data Center
Sioux Falls
SD
57198
US
605 594-6055
gesch@usgs.gov
The data set was assembled at USGS/EROS based upon data from the USGS, the NOAA/National Ocean Service (NOS), the Viriginia Institute of Marine Sciences, the Naval Research Laboratory and the US Army Corps of Engineers.
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; Esri ArcGIS 10.1.0.3035
For the LiDAR only: The expected accuracy of the measured variables are as follows: attitude within 0.07 degree, 3-cm nominal ranging accuracy, and vertical elevation accuracy of +/- 20 cm (bald earth). Quality checks are built into the data-processing software.
For the LiDAR: Flights were conducted during the winter season when clear, windless, and calm conditions persisted. A visual record of each flight was taken. Not applicable for other sources.
Value coded as "NO DATA" indicates areas where no data exists in the ARC/INFO GRID.
Because the source bathymetric, topographic, and LiDAR data vary in density and accuracy, users need to be made aware of the spatially varying quality of the merged model. In some areas, the spacing of the soundings would support gridding at a higher resolution than 1/9-arc second, where in other areas the values of the 1/9-arc-second grid were interpolated based only on distant points. Current work involves generating spatial indices of data quality and accuracy that are coregistered with the model to help users better judge the applicability of the model for their application in a specific location. One index will be a representation of the density (point spacing) of the input sounding data. This index will be helpful for indicating to users the inherent accuracy of the source data, and thus the derived merged model. Without such labeling, users may assume more accuracy than is actually present, especially because the data are presented in a seamless fashion where discontinuities among data sources have been intentionally minimized
The vertical accuracy of the model varies spatially, due mainly to the wide variety of dates and data collection technologies used for source data acquisition. A merged raster model at a uniform grid cell spacing was produced because most users require such a product for their computer mapping systems. Current work involves generating spatial indices of data quality and accuracy that are coregistered with the model to help users better judge the applicability of the model for their application in a specific location. An index will portray the estimated vertical accuracy of the bathymetric and topographic data. This index will be helpful for indicating to users the inherent accuracy of the source data, and thus the derived merged model. Without such labeling, users may assume more accuracy than is actually present, especially because the data are presented in a seamless fashion where discontinuities among data sources have been intentionally minimized, and the vertical units are expressed to sub-meter precision.
U.S. Geological Survey
unknown
USGS National Elevation Dataset (NED)
Reston VA
U.S. Geological Survey
onLine
19490101
19950101
ground condition
DEMs
land elevation information
National Oceanic and Atmospheric Administration
unknown
NOAA hydrographic surveys
Silver Spring MD
National Oceanic and Atmospheric Administration
hardDisk
19450101
19960101
publication date
NOAA
water depth information
A seamless bathymetric/topographic/LiDAR digital elevation model (DEM) was developed by merging topographic LiDAR data from the USGS and bathymetric data from NOAA, the Naval Research Laboratory (NRL), the Virginia Institute of Marine Science (VIMS), and the US Army Corps of Engineers. Each of the datasets was initially processed independently to apply the "best available" criteria to select the data to be merged. Prior to merging, the selected data were transformed to a common reference coordinate system, both horizontally and vertically. The best available bathymetric data were selected with a GIS query procedure that applied spatial and temporal filters to the 122 digital hydrographic surveys, dating from 1870 to 2005, which cover the North Carolina region. The terrestrial elevations were obtained from the LiDAR-based 1/9 arc-second layer of the USGS National Elevation Dataset (NED). Standard tools and datasets (VERTCON and GEOID99) from the National Geodetic Survey were used to transform the bathymetric elevation data into the common vertical reference frame. Bathymetric points were not used where LiDAR points were available. The NED "shoreline" (interface of zero/non-zero elevations) was used to make the final selection of bathymetry and topography points for merging. All land elevations within 20 pixels of the shoreline were converted from raster format to XYZ point data. All bathymetry points coinciding with areas of zero elevation in NED were selected. Because of the age of some of the hydrographic surveys, some of the soundings were located on areas that had been filled and are now represented as land in the DEM. These points were withheld from further processing. The selected topography points within the shoreline buffer zone and the bathymetry points were gridded to produce a raster surface model with a cell size of 1/9 arc-second. The points were input to an implementation of the ANUDEM thin plate spline interpolation algorithm, which is optimized for generation of topographic surfaces. The bathymetry points could have been gridded independently of the topographic data, but the shoreline zone land elevations were included in the interpolation to ensure a better match of the bathymetric and topographic surfaces for the subsequent mosaicing step. To avoid introduction of any interpolation edge effects into the merged elevation model, the output grid from the interpolation was clipped to include only land elevations within 10 pixels of the shoreline. The final processing step involved the mosaicing of the bathymetry grid and the NED elevation grid. The values in the 10-pixel overlap area were blended by weighted averaging, where the weights for each grid are determined on a cell-by-cell basis according to the cell's proximity to the edges of the overlap area. The resulting final merged product is a seamless bathymetric/LiDAR model covering the North Carolina region at a grid spacing of 1/9-arc-second. The vertical coordinates represent elevation in decimal meters relative to the NAVD88 datum, and the horizontal coordinates are decimal degrees of latitude and longitude referenced to the NAD83 datum.
20080201
Tampa Bay topographic/bathymetric DEM
U.S. Geological Survey
Dean Tyler
mailing and physical
EROS Data Center
Sioux Falls
SD
57198
US
605 594-2624
dtyler@usgs.gov
Raster
Pixel
87543
77710
1
8.9831528411952133e-009
8.9831528411952133e-009
Decimal Degrees
D North American 1983
GRS 1980
6378137.0
298.257222101
EROS Data Center
Customer Services Representative
mailing and physical
U.S. Geological Survey EROS Data Center
Sioux Falls
SD
57198
US
605-594-6151
605-594-6589
custserv@edcmail.cr.usgs.gov
topographic/bathymetric/LiDAR DEM
Although these data have been processed successfully on a computer system at the U.S. Geological Survey, EROS Data Center, no warranty expressed or implied is made by either regarding the utility of the data on any system, nor shall the act of distribution constitute any such warranty. The USGS will warrant the delivery of this product in computer-readable format and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer peripherals, or when the physical medium is delivered in damaged condition. Requests for adjustments of credit must be made within 90 days from the date of this shipment from the ordering site.
ARCG
18 GB
http://topotools.cr.usgs.gov/topobathy_viewer/
none
20121217
U.S. Geological Survey
Jo Anne Stapleton
mailing
521 National Center
Reston
VA
20192
US
703 648 4592
703 648 4614
jastapleton@usgs.gov
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
local time