U.S. Geological Survey
2007
MOSAIC_COMP – Composite Sidescan-Sonar Mosaic collected by the U.S. Geological Survey offshore of the Grand Strand, SC (1999 – 2003) (Compressed - MrSID)
1.0
remote-sensing image
Open-File Report
2005-1346
Woods Hole Science Center, Woods Hole, MA
U.S. Geological Survey, Coastal and Marine Geology Program
http://pubs.usgs.gov/of/2005/1346/arcgis/mosaic/mosaic_sid.zip
Baldwin, W.E.
Denny, J.F.
Schwab, W.C.
Gayes, P.T.
Morton, R.A.
Driscoll, N.W.
2007
Edition 1.0
Series_Information Series_Name
Woods Hole Science Center, Woods Hole, MA
U.S. Geological Survey, Coastal and Marine Geology Program
http://pubs.usgs.gov/of/2005/1346/
In 1999, the USGS, in partnership with the South Carolina Sea Grant Consortium, began a study to investigate processes affecting shoreline change along the northern coast of South Carolina, focusing on the Grand Strand region. Previous work along the U.S. Atlantic coast shows that the structure and composition of older geologic strata located seaward of the coast heavily influences the coastal behavior of areas with limited sediment supply, such as the Grand Strand. By defining this geologic framework and identifying the transport pathways and sinks of sediment, geoscientists are developing conceptual models of the present-day physical processes shaping the South Carolina coast. The primary objectives of this research effort are: 1) to provide a regional synthesis of the shallow geologic framework underlying the coastal upland, shoreface and inner continental shelf, and define its role in coastal evolution and modern beach behavior; 2) to identify and model the physical processes affecting coastal ocean circulation and sediment transport, and to define their role in shaping the modern shoreline; and 3) to identify sediment sources and transport pathways; leading to construction of a regional sediment budget.
This data set contains the sidescan-sonar imagery collected offshore of the Grand Strand, SC 1999 - 2003. These data are used in conjunction with surficial sediment analyses to define the sediment distribution within the survey area.
1999
2003
ground condition
None planned
-79.177122
-78.492052
33.876672
33.143971
General
U.S. Geological Survey
USGS
Woods Hole Science Center
WHSC
Coastal and Marine Geology Program
CMGP
sidescan-sonar
sidescan
side scan sonar
backscatter
MrSID image
grey scale image
composite mosaic
ISO 19115 Topic Category
oceans
oceans and coastal
oceans and estuaries
imageryBaseMapsEarthCover
geoscientificInformation
General
South Carolina
Grand Strand
North Myrtle Beach
Myrtle Beach
Surfside
Garden City
Pawleys Island
Waites Island
Southeast United States
United States
Atlantic Ocean
None
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.
U.S. Geological Survey
Jane Denny
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x2311
508-457-2310
jdenny@usgs.gov
http://pubs.usgs.gov/of/2005/1346/images/mosaic.jpg
grey-scale image of sidescan-sonar mosaic
JPEG
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.780
These data measure the acoustic reflectivity of the seafloor. These values (Digital Number (DN)) are a relative measure of reflectivity within the study area and are internally consistent.
These are raster data; all sidescan-sonar data collected during USGS field efforts offshore of Myrtle Beach, SC 1999 – 2003 are included. Processing removed any spurious data.
No additional checks were made for topologic consistency.
DGPS is assumed to be accurate within 1-2 meters. Standard GPS is assumed accurate within 5-10 meters. 99% of the positional data is DGPS. Unless noted, all GPS/DGPS data is referenced to WGS84 (NAD83). Slant-range distance is recorded between the sidescan-sonar tow vehicle and a sidemount rigged with an acoustic transponder. Offset between the sidemount and GPS antennae is measured. Basic trigonomic calculations use the slant-range offset to calculate a 'fish' (tow-vehicle) navigation. An assumption in these calculations is that the tow-vehicle is traveling directly behind the vessel; movement to port or starboard is not accounted for within 'fish' navigation. Thus, the horizontal accuracy of the sidescan-sonar tow-vehicle is 10 meters.
The sidescan-sonar data were acquired with a Benthos (Datasonics) SIS 1000 CHIRP sonar and Edgetech DF-1000 dual-frequency sonar systems. The SIS-100 operates in a frequency range of 100 - 120 kHz; the DF-1000 operates at 100 and 500 kHz. The sidescan-sonar imagery offshore of the Grand Strand is comprised of data acquired on six geophysical cruises operated by the USGS during 1999 - 2003.
All sidescan-sonar data were logged digitally at a sample rate resulting in a 0.18-m pixel size in the across-track direction and approximately 0.14-m in the along-track direction following the methodology outlined in Danforth and others (1991). A median filtering routine (Malinverno and others, 1990) was applied to the sidescan-sonar data to remove speckle noise, resulting in a 0.73-m pixel size. The data for each survey were further processed and digitally mosaicked using PCI Geomatica Software and procedures described in Danforth and others (1991), Danforth (1997), and Paskevich (1992) resulting in an enhanced, geographically correct, sidescan-sonar mosaic with 2 meters/pixel resolution. The composite mosaic was exported as a TIFF image, with an associated ESRI world file.
Danforth, W.W., 1997, Xsonar/ShowImage: A complete system for rapid sidescan-sonar processing and display: U.S. Geological Survey Open File Report 97-686, 77 p.
Danforth, W.W., O'Brien, T.F., and Schwab, W.C., 1991, USGS Image processing system: near real-time mosaicking of high-resolution sidescan-sonar data Sea Technology, Vol 1, p.54-59.
Malinverno, A., Edwards, M, and Ryan, W.B.F, 1990, Processing of SeaMARC swath sonar data: IEEE, Journal of Ocean Engineering, v.15, p. 14-23.
Paskevich, V., 1992, Digital mapping of sidescan-sonar data with the Woods Hole Image Processing System software: U.S. Geological Survey Open-File Report 92-536, 87.p
1999 - 2003
Jane Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x2311
508-457-2310
jdenny@usgs.gov
The sidescan-sonar mosaic was compressed using MrSid. A compression of 20x was used.
2003
Jane Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x2311
508-457-2310
jdenny@usgs.gov
Raster
Pixel
20000
15500
1
Universal Transverse Mercator
17
0.999600
-81.000000
0.000000
500000.000000
0.000000
row and column
4.000000
4.000000
meters
D_WGS_1984
WGS_1984
6378137.000000
298.257224
Band_1
Sidescan-Sonar image stored in MrSid format
ESRI
ObjectID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
Value
pixel values in the range of 0-255; 0 represents low backscatter; 255 represents high backscatter
USGS
0
255
digital number
1
Count
pixel count
USGS
0
249232064
unrepresented
1
There are no attributes associated with a MrSid image. Image pixel values contain acoustic reflectivity values normalized to an 8-bit data range (0-255). Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values).
USGS
U.S. Geological Survey
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700
508-457-2310
Downloadable Data
Although all data have been used by the 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.
MrSID
ArcGIS 9.0
MrSID Image compression
File contains the sidescan-sonar imagery collected offshore of the Grand Strand. SC
MrSID Image Compression
9.428
http://pubs.usgs.gov/of/2005/1346/arcgis/mosaic/mosaic_sid.zip
Data can be downloaded via the World Wide Web (WWW)
DVD-ROM
4.75
Gbytes
UDF
none
This image is available as a compressed MrSID 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 MrSID image.
20070115
Jane Denny
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-548-8700 x2311
508-457-2310
jdenny@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
None
None