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.
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.
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.
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.
Values of the grids are elevation in meters.
MIN MAX MEAN STDV
bathygrd -412.997 -10.196 -131.044 85.165
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.
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://pubsdata.usgs.gov/pubs/of/2002/0391/gb-gridmeta.html
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Page Last Modified: Wednesday, 07-Dec-2016 19:27:37 EST