Identification_Information: Citation: Citation_Information: Originator: Edward M. Sweeney Publication_Date: 2004 Title: Compressed Digital Sidescan-Sonar Mosaic collected within the Gulf of Farallones Geospatial_Data_Presentation_Form: Raster Publication_Information: Publication_Place: Woods Hole, MA Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/of/2004/1082/arcgis/mosaic/farallones_sid.zip Larger_Work_Citation: Citation_Information: Originator: Edward M. Sweeney Originator: William W. Danforth Originator: Herman A. Karl Originator: Thomas F. O'Brien Originator: William C. Schwab Publication_Date: 2004 Title: The Gulf of Farallones: Sidescan-Sonar Imagery Series_Information: Series_Name: Open-File Report Issue_Identification: 2004-1082 Publication_Information: Publication_Place: U.S. Geological Survey, Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/of/2004/1082 Description: Abstract: In 1989, the U.S. Geological Survey (USGS) began a major geologic and oceanographic investigation of the Gulf of the Farallones continental shelf system, designed to evaluate and monitor human impacts on the marine environment (Karl and others, 2002). The study region is located off the central California coast, adjacent to San Francisco Bay and encompasses the Gulf of the Farallones National Marine Sanctuary. Geologic mapping of this area included the use of various remote sensing and sampling techniques such as sub-bottom profiling, sidescan-sonar and bathymetric mapping, gravity core and grab sampling, and photography. These data were used to define the surficial sediment distribution, underlying structure and sea floor morphology of the study area. The primary focus of this report is to present a georeferenced, digital sidescan-sonar mosaic of the study region. The sidescan-sonar data were acquired with the AMS-120 (120kHz) sidescan-sonar system during USGS cruise F9-89-NC. The dataset covers approximately 1000 kmē of the continental shelf between Point Reyes, California and Half Moon Bay, California, extending west to the continental shelf break near the Farallon Islands. The sidescan-sonar mosaic displays a heterogenous sea-floor environment, containing outcropping rock, ripples, dunes, lineations and depressions, as well as flat, featureless sea floor (Karl and others, 2002). These data, along with sub-bottom interpretation and ground truth data define the geologic framework of the region. The sidescan-sonar mosaic can be used with supplemental remote sensing and sampling data as a base for future research, helping to define the local current regime and predominant sediment transport directions and forcing conditions within the Gulf of Farallones. Purpose: These data were acquired during the sidescan-sonar survey completed in the Gulf of the Farallones in August, 1989 by the U.S. Geological Survey and were used to define the geological framework of the region. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19890802 Ending_Date: 19890815 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -123.398630 East_Bounding_Coordinate: -122.674261 North_Bounding_Coordinate: 37.998062 South_Bounding_Coordinate: 37.550340 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: sonar Theme_Keyword: Sidescan-sonar Theme_Keyword: backscatter Theme_Keyword: USGS Theme_Keyword: U.S. Geological Survey Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: field activity identifier F9-89-NC Theme_Keyword: field activity serial number 89020 Theme_Keyword: Woods Hole Science Center Theme_Keyword: imagery Theme_Keyword: AMS-120 Theme_Keyword: seafloor mapping Place: Place_Keyword_Thesaurus: General Place_Keyword: Farallones Place_Keyword: Gulf of the Farallones Place_Keyword: California Place_Keyword: U.S. West Coast Place_Keyword: U.S. Pacific Coast Place_Keyword: North America Place_Keyword: Pacific Ocean Place_Keyword: United States Place_Keyword: Half Moon Bay Place_Keyword: Point Reyes Place_Keyword: Farallon Islands Place_Keyword: Bodega Bay Place_Keyword: San Francisco Access_Constraints: None Use_Constraints: Public domain data from the U.S. government is freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of this dataset. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Edward M. Sweeney Contact_Organization: U.S. Geological Survey Contact_Position: Research Assistant Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2307 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: esweeney@usgs.gov Native_Data_Set_Environment: Microsoft Windows 2000 Version 5.1 (Build 2600) Service Pack 1; ESRI ArcCatalog 8.3.0.800 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: These data were acquired with an AMS-120 (120 kHz) sidescan-sonar system. All data were acquired during one geophysical cruise condcuted in 1989. These data were navigated using GPS and LORAN-C. The horizontal accuracy of these data is roughly +/- 50 meter. Additionally, no layback was estimated for the tow-vehicle. Thus, navigation was based on ship position and not tow-vehicle posistion. Thus, decreasing the horizontal positioning resolution of these data. Logical_Consistency_Report: These data were acquired with an AMS-120 (120 kHz) sidescan-sonar system, and processed following an identical procedure. Completeness_Report: These data are complete. Lineage: Process_Step: Process_Description: The sidescan-sonar data were acquired using an AMS-120 (120 kHz) sidescan-sonar system. The analog signal from the sidescan-sonar tow vehicle was aquired with and stored on a Triton Technologies, Inc. QMIPS data acquisition system, and then transferred to a Masscomp computer and stored on 8mm 54 MB digital data cartridge tapes. Radiometric corrections and geometric distortions were made using USGS software packages Xsonar and Showimage described in Danforth and others (1991) and Danforth (1997). The sidescan-sonar data were further processed and digitally mosaicked using PCI Geomatica Software and procedures described in Paskevich (1992) resulting in an enhanced, geospatially correct, sidescan-sonar mosaic with 4 meter/pixel resolution. The generated mosaic was exported as a TIFF image, with an associated ESRI world file. Adjustment in contrast levels were then made on the TIFF image file using Adobe Photoshp 6.0. The data were then compressed utilizing LizardTech's Mr.Sid compression alogrithm at a compression ratio of 20:1. Process_Date: 2004 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Edward M. Sweeney Contact_Organization: U.S. Geological Survey Contact_Position: Research Assistant Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2307 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: esweeney@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 12400 Column_Count: 15900 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 10 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -123.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 4.000000 Ordinate_Resolution: 4.000000 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: D_WGS_1984 Ellipsoid_Name: WGS_1984 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257224 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: SID Image Entity_Type_Definition: Sidescan-sonar image in SID format Entity_Type_Definition_Source: ESRI 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 and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2275 Contact_Facsimile_Telephone: (580)457-2313 Contact_Electronic_Mail_Address: nsoderberg@usgs.gov Resource_Description: Compressed Sidescan-sonar Mosaic of Gulf of Farallones Distribution_Liability: Although this data set and its lineage have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data or its 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 items. Users must assume responsibility for the proper use of these data. The data should not be used at resolutions for which they are not intended. The data have not been reviewed for conformity with U.S. Geological Survey editorial standards, or the North American Strigraphic code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government. Metadata_Reference_Information: Metadata_Date: 20040407 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Edward M. Sweeney Contact_Organization: U.S. Geological Survey Contact_Position: Research Assistant Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2307 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: esweeney@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Profile_Name: ESRI Metadata Profile Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile