CRLS97007 Sidescan-Sonar Track Lines

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: David C. Twichell
Publication_Date: 20000125
Title: CRLS97007 Sidescan-Sonar Track Lines
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey
Description:
Abstract:
Two 21-day field operations were conducted in 1997 and 1998 in the estuaries and on the inner continental shelf off the northern Oregon and southern Washington coast. These cruises aboard the R/V Corliss were run in order to generate reconnaissance maps of the seafloor geology and the shallow subsurface stratigraphy using sidescan-sonar and seismic-reflection mapping techniques. The 1998 cruise also collected sediment grab samples, bottom photographs, and video images to verify the sidescan-sonar imagery and to document the seafloor geology. The combination of these data with previously collected sediment sample data (Robert, 1974; Nittrouer, 1978; and Smith et. al., 1980) has been used to define the extent and lithology of shelf sediments associated with the Columbia River littoral cell. This work is one component of a larger project studying the erosion of the Washington Oregon coasts and is being coordinated by the U.S. Geological Survey and the Washington State Department of Ecology. The reasons for collecting these data are to provide a regional synthesis of the offshore geology for this project and to support a wide variety of management decisions and to provide a basis for further process-oriented investigations.
Purpose:
This GIS overlay is a component of the Southwest Washington Coastal Erosion ArcView GIS database. This particular overlay contains the ship tracklines from the Corliss 1997 cruise along which sidescan-sonar imagery was collected.
Supplemental_Information:
Roberts, R.W., 1974, Marine sedimentological data of the Washington continental shelf: University of Washington, Department of Oceanography Special Report 57, 129p.

Nittrouer, C.A., 1978, The process of detrital sediment accumulation in a continental shelf environment: an examination of the Washington shelf: PhD Thesis, University of Washington, Seattle, WA. 243p.

Smith, J.M., Messmer, L.W., Phipps, J.B., Samuelson, D.F., and Schermer, E.D., 1980, Grays Harbor and Chehalis River improvements to navigation environmental studies - Grays Harbor ocean disposal study: literature review and preliminary benthic sampling: U.S. Army Corps of Engineers Internal Report.

Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19970827
Beginning_Time: 20040000Z
Ending_Date: 19970913
Ending_Time: 22200000Z
Currentness_Reference: Publication Date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -124.500000
East_Bounding_Coordinate: -123.800000
North_Bounding_Coordinate: +47.350000
South_Bounding_Coordinate: +45.900000
Keywords:
Theme:
Theme_Keyword_Thesaurus: General
Theme_Keyword: Corliss
Theme_Keyword: CRLS97007
Theme_Keyword: ship trackline
Theme_Keyword: navigation
Theme_Keyword: vector
Theme_Keyword: ArcView
Theme_Keyword: shapefile
Place:
Place_Keyword_Thesaurus: General
Place_Keyword: Pacific Ocean
Place_Keyword: Washington
Place_Keyword: Oregon
Place_Keyword: WA
Place_Keyword: OR
Place_Keyword: Inner shelf off Columbia River
Place_Keyword: Columbia River Littoral Cell
Access_Constraints: None
Use_Constraints:
The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David C. Twichell
Contact_Organization: U.S. Geological Survey
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address:
U.S. Geological Survey
Woods Hole Field Center
384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: dtwichell@usgs.gov
Data_Set_Credit: Seafloor Mapping Group
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
These navigational lines actually represent the ship's position. No instrumentation was available to estimate a range to the sidescan-sonar towfish. However, most of the data were acquired in fairly shallow water, therefore the layback (wire out) was minimal.
Quantitative_Attribute_Accuracy_Assessment:
Attribute_Accuracy_Value: 10-20m
Attribute_Accuracy_Explanation: This accuracy is dependant on the amount of cable out for the sidescan-sonar towfish - hence tied to water depth.
Logical_Consistency_Report:
The towfish was typically kept 10 m above the bottom of the seafloor as determined from the first sidescan-sonar return. The water depth determined the amount of wire out to maintain this fish altitude. Hence, in shallower water, less wire out and in turn a more accurate representation of fish location as related to the ship's position.
Completeness_Report:
These tracklines represent only where sidescan-sonar data were collected. The navigation is sent directly to the sidescan-sonar acquisition computer and merged with the data.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The ship was navigated with P-CODE GPS. No instrumentation was available to estimate the range to the sidescan-sonar towfish. Therefore these tracklines represent ship's position, not towfish position. However, for the purposes of this study, these tracklines are also used to map the sidescan-sonar imagery.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value: 10-20 meters
Horizontal_Positional_Accuracy_Explanation: P-CODE GPS is assumed to be accurate within 10-20 meters.
Lineage:
Process_Step:
Process_Description:
These tracklines were generated from the navigation merged with the sidescan-sonar data. This navigation was downsampled from the original fix every 10 seconds to a navigational fix every 1 minute. Obviously bad navigation points were removed. Each line segment represents the navigation for the corresponding sidescan-sonar imagery. Each line segment has attribute information indicating which sidescan-sonar line this ship navigation corresponds to. A single sidescan-sonar line can have multiple segments reflecting acquisition interruptions, navigational glitches, or other potential line breaks. In addition to line number, each vector also contains sidescan-sonar acquisition information. The recording computer can store information as 8-bit or 16-bit. The "acquired" field of each vector indicates which format the raw data was stored in.
Process_Date: 19970900
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: VeeAnn A. Cross
Contact_Organization: U.S. Geological Survey
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: mailing and physical address
Address:
U.S. Geological Survery
Woods Hole Field Center
384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: 508-548-8700
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: 0.00018
Longitude_Resolution: 0.00026
Geographic_Coordinate_Units: Decimal degrees
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257222101
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: track97.dbf
Entity_Type_Definition: ArcView shapefile attribute table
Entity_Type_Definition_Source: ESRI
Attribute:
Attribute_Label: Linenum
Attribute_Definition:
Line number corresponding to the sidescan-sonar imagery line collected.
Attribute_Definition_Source: watch stander on CRLS97007 cruise
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 47
Attribute:
Attribute_Label: Acquired
Attribute_Definition:
Describes the original format in which the sidescan-sonar data corresponding to this line segment was stored. The imagery is either stored as 8-bit or 16-bit, with the 16-bit imagery having a much broader range of values.
Attribute_Definition_Source: data processor
Attribute_Domain_Values:
Unrepresentable_Domain: character field
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Nancy Soderberg
Contact_Organization: U.S. Geological Survey
Contact_Position: Data Librarian
Contact_Address:
Address_Type: mailing address
Address:
U.S. Geological Survey
Woods Hole Field Center
384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700
Contact_Facsimile_Telephone: 508-457-2313
Contact_Electronic_Mail_Address: nsoderberg@usgs.gov
Resource_Description: U.S. Geological Survey CD-ROM Open-File Report
Distribution_Liability:
This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ARCV
File_Decompression_Technique: No compression applied
Digital_Transfer_Option:
Offline_Option:
Offline_Media: CD-ROM
Recording_Capacity:
Recording_Density: 650
Recording_Density_Units: MBytes
Recording_Format: ISO 9600 with Rock Ridge extensions
Compatibility_Information: UNIX, DOS, MAC
Fees: none at this time
Technical_Prerequisites:
These tracklines are available in ArcView shapefile format. The user must have ArcView, Arc Explorer, or another GIS package capable of importing and reading these data.
Metadata_Reference_Information:
Metadata_Date: 20000104
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: VeeAnn A. Cross
Contact_Organization: U.S. Geological Survey
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: mailing and physical address
Address:
U.S. Geological Survey
Woods Hole Field Center
384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: 19940608

Generated by mp on Tue Jan 25 17:52:03 2000