U.S. Geological Survey, 2009, seismic_sht_07007.shp - Shot points at 500 shot intervals for chirp seismic-reflection data collected by the U.S. Geological Survey offshore of the Chandeleur Islands, LA, 2007 (points): Open-File Report 2008-1195, 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:
Baldwin, Wayne E. , Pendleton, Elizabeth A. , and Twichell, David C. , 2009, Geophysical Data from offshore of the Chandeleur Islands, Eastern Mississippi Delta: Open-File Report 2008-1195, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. 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.
Coordinates defining the features.
(508) 548-8700x2266 (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov
This data set contains seismic shot locations at 500 shot intervals for approximately 1655 km of EdgeTech 512i chirp seismic-reflection data collected by the U.S. Geological Survey during a 2007 geophysical cruise offshore of the Chandeleur Islands, LA.
U.S. Geological Survey.
Person who carried out this activity:
(508) 548-8700x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Person who carried out this activity:
(508) 548-8700x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Person who carried out this activity:
(508) 548-8700x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Person who carried out this activity:
(508) 548-8700x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Stockwell, John, 2008, CWP/SU: Seismic Uni*x: Center for Wave Phenomena - Colorado School of Mines, Golden, CO.Online Links:
Henkart, Paul, 2007, SIOSEIS: Scripps Institution of Oceanography, University of California - San Diego, LaJolla, CA.Online Links:
Michael W. Norris and Alan K. Faichney, 2002, SEGY Rev.1 Data Exchange Format1: Society of Exploration Geophysicists, Tulsa, OK.Online Links:
All attributes were checked in a consistent manner.
The SB-0512i was towed approximately 6 m astern and approximately 1.5 m below the sea surface. DGPS navigation (assumed to be accurate within 1-2 m) was obtained from the receiver mounted above the interferometric sonar head, but towfish layback was not accounted for. The layback of the towfish adds additional uncertainty due to changes in angle and scope of the tow cable in response to sea state and vessel speed. The use of J-Star acquisition software during the ACAD07007 cruise caused a reduction in the resolution of navigation values recorded to the trace headers from the onboard DGPS. During acquisition, J-Star truncates the three least significant digits from the raw navigation string, which reduces the resolution of each navigation fix on the order of 1-2 meters. This error is evident in the ship-track polylines in the shapefile "seismic_trk_07007.shp", which display a "sawtooth" pattern when viewed at scales finer than approximately 1:3000. Based on horizontal offsets between the fish and GPS receiver, fish motion behind the vessel, and error associated with the acquisition system, the resulting positional accuracy is assumed to be +/- 20 m.
All navigation from seismic-reflection data collected during cruise ACAD07007 was used to generate this shapefile.
Any spurious data points were removed during processing.
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 as the originator of the dataset.
(508) 548-8700x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Downloadable Data
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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: | This WinZip file contains a shapefile of 512i seismic-reflection profile shot points collected during cruise ACAD07007 offshore of the Chandeleur Islands, LA, and the associated metadata. It also contains a comma-separated text file (seismic_shtunique_07007.csv), which contains every unique shot point for the same survey. in format WinZip (version 9.0) Size: 17.340 Mbytes |
|---|---|
| Network links: |
<http://pubs.usgs.gov/of/2008/1195/GIS_catalog/Tracklines/seismic_sht_07007.zip> |
| Media you can order: |
DVD-ROM
(Density 4.75
Gbytes)
(format UDF)
|
This zip file contains data available in Environmental Systems Research Institute (ESRI) point shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.
(508) 548-8700x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
