Open-File Report 02-391
This data set consists of bathymetric data of Glacier Bay, Alaska. The data are published as ESRI GRID format where interpolations have been calculated across nodata gaps that were no more than 30 meters wide.
Data were collected during May 29 - June 6, 2001, by contract with Thales Geosolutions (<http://www.thales-geopacific.com/>) aboard the R/V Davidson as part of a cooperative survey conducted by the U.S. National Park Service and the U.S. Geological Survey (Biological Resources and Coastal and Marine Geology). The instrument was a Reson 8111 multibeam echosounder (<http://reson.com/sb8111.htm>). The raw data were reduced by Thales.
Additional information about the field activities from which this data set was derived are available online at <http://walrus.wr.usgs.gov/infobank/d/d101gb/html/d-1-01-gb.meta.html>
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Specifications for the Reson SeaBat 8111 Multibeam Echosounder (<http://www.reson.com/sb8111.htm>)
Operating frequency: 100 kHz
Number of beams: 101
Beamwidth across track: 1.5 degrees
Beamwidth along track: 1.5 degrees
Center-to-center beam separation: 1.5 degrees
Pulse length: Variable, operator selectable
Depth range: 3 - 1000 meters
Transducer depth rating: 100 meters
Max. update rate: 35 swaths per second
Max. vessel Speed: 20 knots
Stabilization: Pitch stabilization within 10 degrees
Projector beam control: External pitch sensor
Hydrophone size (Dia./arc/length): 640mm, 220 degrees, 200mm
Processor Dimensions (HWD): 177 x 483 x 434 mm
Tranceiver Dimensions (HWD): 267 x 450 x 427 mm
Weight: (with 15m cable):
Hydrophone Dry: 42 kg Wet: 36 kg
Projector Dry: 30 kg Wet: 23 kg
Transceiver weight: 13.6 kg
Processor weight: 20 kg
Although this Federal Geographic Data Committee-compliant metadata
file is intended to document the data set in nonproprietary form,
as well as in ArcInfo format, this metadata file may include some
ArcInfo-specific terminology.
Wong, Florence L. , Stevenson, A.J., and Dartnell, Peter, 2002, BATHYGRD -- 5-m bathymetric grid of Glacier Bay: USGS Open-File Report 03-391, U.S. Geological Survey, Menlo Park, California.Online Links:
This is a Raster data set. It contains the following raster data types:
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 5.0
Ordinates (y-coordinates) are specified to the nearest 5.0
Planar coordinates are specified in Meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is GRS1980.
The semi-major axis of the ellipsoid used is 6378206.4.
The flattening of the ellipsoid used is 1/294.98.
Values of the grids are elevation in meters.
MIN MAX MEAN STDV
bathygrd -412.997 -10.196 -131.044 85.165
(650) 329-5327 (voice)
(650) 329-5190 (FAX)
fwong@usgs.gov
These data are intended for science researchers, students, policy makers, and the general public. The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information.
For the interpolated grid GLACIER05MIG, the point coverage for each block was merged with adjoining blocks, the grid IDW function was applied with default options, and the resulting grid clipped to the boundary of the block. All the interpolated grids were merged into a continuous grid GLACIER05MIG that was corrected by a mask that omitted data in holes that exceede 30 meters in width.
The masking grid was constructed as follows: a unit grid (data cells = 1, all others = nodata) was copied from GLACIER05MG. The unit grid was converted to a polygon coverage from which polygons with areas of less than 1000 square meters were removed in bulk. The remaining interior polygons were inspected in Arcedit and removed if the width were about 30 meters or less. This polygon coverage was converted back to a grid to be applied as a mask to the merged grids described in the previous paragraph.
Not applicable.
Navigation was multiple DGPS [differential global positioning systems] coupled up with 2 very precise DR [dead-reckoning] 3-axis accelerometers, all integrated in WinFrog (proprietary software from Thales Geosolutions <http://www.thales-geopacific.com/offshore/>). The best functional test we did was crossties, which suggested that average navigational errors were on the order of 1 meter, with (rare) maximum errors being about 3 meters. (A.J. Stevenson, written communtication, October 2001)
Data values are missing in and around shallow or emergent features (islands) and where adjoining trackline coverage was not overlapping.
Not applicable for raster data.
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- None
- Use_Constraints:
- Data not to be used for navigational purposes.
(650) 329-5327 (voice)
(650) 329-5190 (FAX)
fwong@usgs.gov
Please recognize the U.S. Geological Survey (USGS) as the source of this information.Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.
The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.
(650) 329-5327 (voice)
(650) 329-5190 (FAX)
fwong@usgs.gov
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://pubsdata.usgs.gov/pubs/of/2002/0391/gb-gridfaq.html
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Wednesday, 07-Dec-2016 19:27:36 EST