U.S. Geological Survey
NOAA National Ocean Service
Coastal and Marine Geology Program - USGS
20050714
Puget Sound topographic/bathymetric DEM
raster digital data
http://chartmaker.ncd.noaa.gov/bathytopo/
This data set is a hybrid elevation model created from USGS topography, NOAA bathymetry, and USGS SHOALS data.
This data set is intended for geospatial applications that require seamless land elevation and water depth information in coastal environments.
1934
2003
ground condition
As needed
-123.160370
-122.199630
48.168056
47.043796
none
elevation
mapping
bathymetry
DEM
digital elevation model
topography
SHOALS
LIDAR
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
WA
USGS Geographic Names Information System
Puget Sound
none
Washington
Manatee County
Island County
Snohomish County
Kitsap County
Jefferson County
King County
Mason County
Pierce County
Thurston County
Puget Sound
none
NOT TO BE USED FOR NAVIGATION
Dean Gesch
U.S. Geological Survey
mailing and physical address
EROS Data Center
Sioux Falls
SD
57198
USA
605 594-6055
gesch@usgs.gov
The data set is a joint effort between the USGS Earth Resources Observation and Science (EROS), the NOAA/National Ocean Service (NOS)/Coast Survey Development Laboratory, and Coastal and Marine Geology Program of the USGS.
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535
not applicable
Value coded as "NO DATA" indicates areas where no data exists in the ARC/INFO GRID.
Positional Accuracy:
Because the source bathymetric and topographic 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 much higher resolution than 1/3 arc-second, where in other areas the values of the 1/3 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 7.5-minute DEMs
Reston VA
U.S. Geological Survey
digital file
1943
1987
ground condition
DEMs
land elevation information
National Oceanic and Atmospheric Administration
Unknown
NOAA hydrographic surveys
Silver Spring MD
National Oceanic and Atmospheric Administration
digital
1934
1999
publication date
NOAA
water depth information
USGS Coastal and Marine Geology Program
2003
USGS Bathymetric LIDAR (SHOALS)
Coastal and Marine Geology Program - USGS
20030924
20030929
ground condition
Coastal and Marine Geology Program - USGS
SHOALS bathymetric LIDAR
A seamless bathymetric/topographic digital elevation model (DEM) was developed by merging the "best available" bathymetric data from NOAA and topographic data from USGS. 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. 2,830,000 USGS SHOALS points (non-terrestrial) were included where available.
The best available bathymetric data were selected with a GIS query procedure that applied spatial and temporal filters to the 41 digital NOAA hydrographic surveys, dating from 1934 to 1999, which cover the Puget Sound region. Approximately 575,000 soundings were transformed from multiple orthometric and tidal vertical datums to a common vertical reference, the NAD83 ellipsoid (GRS80).
The best available topographic data were selected from the USGS National Elevation Dataset (NED). NED is a seamless raster elevation data set that provides national U.S. coverage at a grid spacing of 1/3 arc-second (approximately 10-meters). NED is derived from source DEM's that have a resolution of 10-meters. NED production includes the following processing steps performed on the individual source 7.5-minute DEM files: datum and coordinate unit conversion (horizontal and vertical), projection transformation and resampling, filtering (for removal of production artifacts), mosaicing, edge matching, and metadata generation. The resulting data set includes an elevation value (expressed in decimal meters referenced to NAVD88) posted every 1/3 arc-second on a latitude/longitude grid (referenced to the NAD83 horizontal datum).
The Puget Sound region was extracted from NED. Standard tools and datasets (VERTCON and GEOID99) from the National Geodetic Survey were used to transform the elevation data into the common ellipsoid vertical reference frame. 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 200 meters 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 1/3 arc-second grid spacing to match the resolution of NED. 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 100 meters of the shoreline. The final processing step involved the mosaicing of the bathymetry/SHOALS grid and the NED elevation grid. The values in the 100-meter 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/topographic model covering the Puget Sound region at a grid spacing of 1/3 arc-second. The vertical coordinates represent elevation in decimal feet relative to the GRS80 ellipsoid, and the horizontal coordinates are decimal degrees of latitude and longitude referenced to the NAD83 datum.
DEMs
NOAA
SHOALS
Unknown
Dean Gesch
U.S. Geological Survey
mailing and physical address
EROS Data Center
Sioux Falls
SD
57198
USA
605 594-6055
gesch@usgs.gov
Puget Sound region
Raster
Grid Cell
12142
10376
1
0.00009259
0.00009259
Decimal degrees
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.257222
North American Vertical Datum of 1988
.001
meters
Explicit elevation coordinate included with horizontal coordinates
Customer Services Representative
EROS Data Center
mailing and physical address
U.S. Geological Survey EROS Data Center
Sioux Falls
SD
57198
USA
605-594-6151
605-594-6589
custserv@edcmail.cr.usgs.gov
topographic/bathymetric 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
487.439
http://chartmaker.ncd.noaa.gov/bathytopo
none
20050714
Jo Anne Stapleton
U.S. Geological Survey
mailing address
521 National Center
Reston
VA
20192
USA
703 648 4592
703 648 4614
jastapleton@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
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ESRI Metadata Profile
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ESRI Metadata Profile
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ESRI Metadata Profile
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ESRI Metadata Profile