The geophysical mapping utilized a suite of high-resolution instrumentation to map the surficial sediment distribution, depth and sub-surface geology: dual-frequency 100/500 KHz sidescan-sonar system, 234-KHz interferometric sonar, and 500 Hz -12 KHz chirp sub-bottom profiler. The survey was conducted aboard the M/V Megan Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 km to 5-km offshore of the south shore of Martha's Vineyard, and ranges in depth from ~ 5 to 20 meters.
U.S. Geological Survey, 2009, BATHY_2M_ASC.ASC: Bathymetric data collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007 (ASCII RASTER): Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.This is part of the following larger work.Online Links:
- <https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Bathy/bathy_2m.zip>
- <https://pubs.usgs.gov/of/2008/1288/html/gis.html>
Denny, J.F., Danforth, W.W., Foster, D.S., and Sherwood, C.R., 2009, Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts: Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.Online Links:
This is a Raster data set. It contains the following raster data types:
Planar coordinates are encoded using row and column
Abscissae (x-coordinates) are specified to the nearest 2.000534
Ordinates (y-coordinates) are specified to the nearest 2.000534
Planar coordinates are specified in meters
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.
U.S. Geological Survey
(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov
This bathymetric data set will be used to define the seafloor morphology in the vicinity of the Martha's Vineyard Coastal Observatory and to provide initial conditions for wave and circulation modeling.
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Pitch, roll, heading, and heave information were recorded using a Coda Octopus F180R motion reference unit (MRU) (see: <http://www.codaoctopus.com/motion/f180/index.asp>) and transmitted via network connection to the SWATHplus data collection software. The MRU sensor was mounted directly above the SWATHplus transducers, thereby minimizing "lever arm" offsets which can lead to positioning and depth errors in the bathymetric data. The F180R series MRU uses two L1 antennas for position and heading accuracy. These were mounted directly above the MRU with an offset of 6.76 meters. The antennas are mounted on a rigid horizontal pole with a separation of 1 meter and are offset from the MRU in a forward/aft configuration. The forward offset of the primary antenna from the MRU is 0.5 meters, with no port/starboard offset.
Sound Velocity Profiles (SVP): Fourteen sound velocity casts were collected at various intervals during the USGS cruise 07011 using an Applied Microsystems SV Plus v2 instrument (see <http://www.appliedmicrosystems.com/products/productDetails.aspx?id=1> for details). Sound velocity profiles (SVP) were generally collected at the eastern and western ends of the survey area, corresponding to the start and/or end of geophysical line data collection. This procedure was primarily followed to coordinate collection of SVP casts with the beginning or end of trackline. This was acceptable because only small variations in the speed of sound were noted throughout the survey area and negligible refraction artifacts were visible within the swath bathymetric data.
Primary navigation antenna to MRU: Height offset: -6.76 meters Forward offset: 0 meters Starboard offset: 0 meters
Draft of the MRU below water line: 2.6 meters.
Offset of SWATHplus transducer 1 (port side) from the CRP: Height offset: 0.158 meters Forward offset: -0.019 meters Starboard offset: -0.11 meters
Offset of SWATHplus transducer 2 (starboard side) from the CRP: Height offset: 0.158 meters Forward offset: -0.019 meters Starboard offset: 0.11 meters
Software: SWATHplus 3.05.19
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Software: SWATHplus 3.05.19
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Software: SWATHplus 3.05.19
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Software: SWATHplus 3.05.19
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Software: CARIS HIPS/SIPS 6.1
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Software: IVS DMagic 6.7.0
Person who carried out this activity:
(508) 548-8700x2274 (voice)
5084572310 (FAX)
bdanforth@usgs.gov
Differential Global Positioning System (DGPS) navigation data were acquired with the forward, or primary, Coda Octopus F180R Motion Reference Unit (MRU) DGPS antenna and transmitted via a network connection to the SWATHplus data collection software. The F180R MRU is part of the rigid sidemount used to deploy the SWATHplus bathymetric system, and is mounted on the bracket holding the SWATHplus transducers. The F180R MRU consists of 2 L1 antennas used for position and heading. The antennas are mounted on a rigid horizontal pole, 6.76 meters above the F180R MRU, offset in a forward/aft configuration (see 'source contribution' for a full description of the F180R). DGPS accuracy is 1 to 3 meters, depending on the distance from a US Coast Guard coastal repeater station (<http://www.navcen.uscg.gov/>).
Bathymetric data were ultimately referenced to a local vertical datum. The Woods Hole Oceanographic Institution Martha's Vineyard Coastal Observatory (MVCO) maintains an instrumented node at a depth of 12 meters that records a variety of oceanographic data including water level heights above the node (<http://www.whoi.edu/mvco/description/description2.html>). Oscillation of the water level above the node is recorded in a file that was downloaded and parsed for these heights (OcnDat_s, see: <http://www.whoi.edu/mvco/data/oceandata.html>). These heights are referenced to a vertical datum of 11.68 meters, which represents a long term mean depth directly above the node (August 2006 - present). These data are not tied into any chart datum (i.e. Mean Lower Low Water). We chose to use the local water level heights because other oceanographic data from the 12-meter node will be used in conjunction with the bathymetric grid for oceanographic modeling. All data will be referenced to the local vertical datum at the 12-meter node.
All bathymetric data collected during USGS cruise 07011 off of the south shore of Martha's Vineyard were used to generate the bathymetric grid. Tie lines that fell close to areas of obstruction (e.g. MVCO 12-m node and tower), were not included in the final grid due to poor data quality.
All bathymetric data were collected during USGS cruise 07011 using a SWATHplus swath bathymetric system and a Coda Octopus F180R motion reference unit. Quality control was conducted during processing of the data. Any spurious data or artifacts were removed or minimized.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- These data are not to be used for navigation. 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) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@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: | WinZip file containing bathymetric grid and associated metadata collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, 2007. in format WinZip (version 9.0) Size: 8150 KB |
|---|---|
| Network links: |
<https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Bathy/bathy_2m.zip> |
The grid contained in the zip file is available as an ESRI ASCII grid. To utilize this data, the user must have a GIS software package capable of reading ASCII grids with ESRI headers, or be able to manipulate an ASCII matrix with a geospatial header.
(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov
