Twichell, David, Cross, VeeAnn, and Danforth, William, 2005, SIS1000UN_GEOG.TIF - Unenhanced SIS-1000 sidescan sonar mosaic of a minibasin on the Louisiana upper continental slope - geographic, WGS84: Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.This is part of the following larger work.Online Links:
D.C., Twichell, V.A., Cross, Paskevich, V.F., Hutchinson, D.R., Winters, W.J., and Hart, P.E., 2005, GIS of selected geophysical and core data in the northern Gulf of Mexico continental slope collected by the U.S. Geological Survey: Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.Online Links:
This is a Raster data set. It contains the following raster data types:
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is D_WGS_1984.
The ellipsoid used is WGS_1984.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
Sequential unique whole numbers that are automatically generated.
(508) 548-8700 x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
This GeoTIFF image is a 2 m version of a sidescan sonar mosaic collected using a Benthos SIS-1000 sidescan sonar system. The sonar mosaic has been enhanced and projected to geographic using the WGS 84 datum. This sidescan sonar mosaic was collected on the upper Louisiana continental slope in water depths less than 800 m, and covers an area of 329 km2. Results have been briefly summarized by Cooper et al. (1999).
Data sources produced in this process:
Person who carried out this activity:
508-548-8700 x 2251 (voice)
508-457-2310 (FAX)
vatnipp@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
(508) 548-8700 x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
Person who carried out this activity:
(508) 548-8700 x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
(508) 548-8700 x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
Data sources produced in this process:
Foster, D.F., Twichell, D.C., Danforth, W.W., Irwin, B.J., Nichols, D.R., and O'Brien, T.F., 2000, Archive of SIS-1000 CHIRP subbottom data collected during USGS cruise GYRE 99002 Gulf of Mexico, 9-22 April, 1999: Open-File Report 99-586, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.
Danforth, W.W., O'Brien, T.F., and Schwab, W.W., USGS image processing system: near real-time mosaicking of high-resolution sidescan-sonar data: Sea Technology January, 1991, Marine Technology Society.
Paskevich, V., 1992, Digital mapping of side-scan sonar data with the Woods Hole Image Processing System software: Open-File Report 92-536, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.
Paskevich, V., MAPIT: An improved method for mapping digital sidescan sonar data using the Woods Hole Image Processing System (WHIPS) software: Open-File Report 96-281, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.
Cooper, A, Twichell, D, and Hart, P, 1999, A seismic-reflection investigation of gas hydrates and sea-floor features of the upper continental slope of the Garden Banks and Green Canyon regions, northern Gulf of Mexico: Open-File Report 99-570, U S Geological Survey, Reston, VA.
There are no attributes associated with the image.
The ship was navigated with differential GPS, and location of the deep-towed sidescan vehicle was calculated in a variety of ways. In shallow water an acoustic ranging system was used in concert with vehicle depth and ship heading to compute vehicle location. In deeper water depths where the acoustic ranging system did not work, vehicle location was calculated in one of two ways. In some places the amount of wire out was used in place of the acoustic range. In other places, vehicle location was calculated by measuring the offset between features observed on the NOAA multibeam bathymetry and the tow vehicle echo sounder. This offset was measured at several points along each track and was used to compute vehicle navigation. Vehicle location was interpolated between the measured points. Comparison of features on the surface-towed seismic data with the same features on the deep-towed seismic data indicates that the offset mostly is less than 100 m.
All sidescan data collected for the survey of this basin were included in the mosaic even though rough weather degraded the quality of part of the southernmost line.
All these data were collected using the USGS SIS-1000 sidescan sonar. The data were all collected using a 1500 m total swath width. At the end of the first line, however, it was realized that the system scanning approximately 600 m rather than 750 m to each side of the tow vehicle, and the survey track lines were adjusted to account for this shorter swath width.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
(508) 548-8700 x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
Downloadable Data
Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
| Data format: | A GeoTIFF image and associated world file. in format TIFF GeoTIFF Size: 61.976 |
|---|---|
| Network links: |
<http://pubs.usgs.gov/of/2005/1071/data/sidescan/sis1000/raw/geog/sis1000un_geog.zip> |
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This image is available as a GeoTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GEOTIFF image.
(508) 548-8700 x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
