Backscatter C [8101]--Offshore of San Francisco, California

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Peter Dartnell
Originator: Mercedes D. Erdey
Originator: Rikk G. Kvitek
Originator: Carrie K. Bretz
Publication_Date: 2014
Title: Backscatter C [8101]--Offshore of San Francisco, California
Edition: 1.0
Geospatial_Data_Presentation_Form: GeoTiff
Larger_Work_Citation:
Citation_Information:
Originator: Guy R. Cochrane
Originator: Samuel Y. Johnson
Originator: Peter Dartnell
Originator: H. Gary Greene
Originator: Mercedes D. Erdey
Originator: Nadine E. Golden
Originator: Stephen R. Hartwell
Originator: Charles A. Endris
Originator: Michael W. Mansion
Originator: Ray W. Sliter
Originator: Rikk G. Kvitek
Originator: Janet T. Watt
Originator: Stephanie L. Ross
Originator: Terry R. Bruns
Publication_Date: 2015
Title:
California State Waters Map Series--Offshore of San Francisco Map Area, California
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: Open-File Report
Issue_Identification: OFR 2015-1068
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: <https://dx.doi.org/10.3133/ofr20151068>.
Online_Linkage: <https://pubs.usgs.gov/of/2015/1068/>
Larger_Work_Citation:
Citation_Information:
Originator: Nadine E. Golden
Publication_Date: 2013
Title: California State Waters Map Series Data Catalog
Geospatial_Data_Presentation_Form: database
Series_Information:
Series_Name: Data Series
Issue_Identification: DS 781
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: <https://pubs.usgs.gov/ds/781/>

Description:
Abstract:
This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate grids depending on mapping system used and processing techniques. The raster data file is included in "BackscatterC_8101_2008_OffshoreSanFrancisco.zip," which is accessible from <https://pubs.usgs.gov/ds/781/OffshoreSanFrancisco/data_catalog_OffshoreSanFrancisco.html>.

The acoustic-backscatter map of the Offshore of San Francisco Map Area, California was generated from backscatter data collected by Fugro Pelagos and by California State University, Monterey Bay (CSUMB). Mapping was completed between 2004 and 2008, using a combination of 400-kHz Reson 7125 and 244-kHz Reson 8101 multibeam echosounders. Within the final imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and composition. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones).
Purpose:

These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software. These data are not intended to be used for navigation.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 2004
Ending_Date: 2008
Currentness_Reference: ground condition

Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed

Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -122.62
East_Bounding_Coordinate: -122.42
North_Bounding_Coordinate: 37.86
South_Bounding_Coordinate: 37.70

Keywords:
Theme:
Theme_Keyword_Thesaurus: Global Change Master Directory (GCMD)
Theme_Keyword: Oceans > Bathymetry/SeafloorTopography > Bathymetry
Theme_Keyword: Oceans > Bathymetry/SeafloorTopography > Seafloor Topography
Theme:
Theme_Keyword_Thesaurus: General
Theme_Keyword: Marine Geology
Theme_Keyword: Multibeam
Theme_Keyword: Geology
Theme_Keyword: Bathymetry
Theme_Keyword: Backscatter
Theme_Keyword: Intensity
Theme_Keyword: Ocean Floor Topography
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Pacific Coastal and Marine Science Center
Theme_Keyword: CSMP
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: geoscientificInformation
Theme_Keyword: imageryBaseMapsEarthCover
Theme_Keyword: oceans
Place:
Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: San Francisco
Place_Keyword: State of California
Access_Constraints: None

Use_Constraints:
Please recognize the U.S. Geological Survey (USGS) and California State University, Monterey Bay, Seafloor Mapping Lab (CSUMB). USGS-authored or produced data and information are in the public domain. This information is not intended for navigational purposes.

Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data.

Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.

This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Peter Dartnell
Contact_Organization:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Contact_Position: Physical Scientist
Contact_Address:
Address_Type: mailing and physical address
Address: 400 Natural Bridges Dr.
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060-5792
Country: USA
Contact_Voice_Telephone: (831) 460-7415
Contact_Facsimile_Telephone: (831) 427-4709
Contact_Electronic_Mail_Address: pdartnell@usgs.gov

Browse_Graphic:
Browse_Graphic_File_Name:
<https://pubs.usgs.gov/ds/781/OffshoreSanFrancisco/images/BackscatterC_8101_2008_OffshoreSanFrancisco.jpg>

Browse_Graphic_File_Description: Acoustic backscatter imagery of offshore San Francisco.

Browse_Graphic_File_Type: JPEG

Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report: Not applicable for raster data.
Logical_Consistency_Report: Unspecified
Completeness_Report: Complete

Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Estimated to be no less than 2 m, owing to water depth and total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations.

Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report: Not applicable to acoustic-backscatter imagery.

Lineage:
Process_Step:
Process_Description:
During the mapping missions, an Applanix position and motion compensation system (POS/MV) was used to accurately position the vessel during data collection, and it also accounted for vessel motion such as heave, pitch, and roll (position accuracy, +/-2 m; pitch, roll, and heading accuracy, +/-0.02 degress; heave accuracy, +/-5 percent, or 5 cm). KGPS altitude data (Fugro Pelagos, StarFix HP & XP units; CSUMB, NavCom 2050) were used to account for tide cycle fluctuations and sound velocity profiles were collected with an Applied Microsystems SVPlus sound velocimeter. Soundings were corrected for vessel motion using the Applanix POS/MV data, for variations in water-column sound velocity using the AM SVPlus data, and for variations in water height (tides) using vertical-position data from the KGPS receivers. Backscatter data were processed using Geocoder in both Fugro Pelagos Modified Test Release 16 and Caris HIPS/SIPS versions. Within Geocoder, geobars were created using both the beam averaging and time series engines. Intensities were radiometrically corrected (including despeckling and angle varying gain adjustments) and the position of each acoustic sample was geometrically corrected for slant-range on a line-by-line basis. The contrast and brightness of some geobars were adjusted to better match the surrounding geobars. Individual geobars were mosaicked together at 1- and 2-m resolution using the auto seam method. The mosaics were then exported as georeferenced TIFF images, imported into a GIS, and converted to GRIDS at 2-m resolution.

Process_Date: 2008
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Carrie Bretz
Contact_Organization: Seafloor Mapping Lab, California State University Monterey Bay
Contact_Position: Projects Manager, GIS & Metadata Supervisor
Contact_Address:
Address_Type: mailing and physical address
Address: 100 Campus Center, Bldg 13
City: Seaside
State_or_Province: CA
Postal_Code: 93955
Country: USA
Contact_Voice_Telephone: (831) 582-4197
Contact_Electronic_Mail_Address: carrie_bretz@csumb.edu

Process_Step:
Process_Description:
California Seafloor Mapping Project 1- and 2-m resolution backscatter imagery (CSMP survey blocks CC-00, CC-01, and SF West Bay) within this map were downloaded from California State University, Monterey Bay, Seafloor Mapping Lab (<http://seafloor.csumb.edu/SFMLwebDATA.htm>) and converted to grids. USGS also received original 2004 and 2005 CSUMB San Fancisco Mouth Caris project files and original mapping line files. Backscatter data were reprocessed using the Caris HIPS/SIPS version of Geocoder similar to the method described in the Processing Step above. Backscatter grids of similar mapping systems were merged in a GIS and clipped to the boundary of the map area. Grids from different mapping systems were not merged together due to different mapping frequencies and processing techniques.

Process_Date: 2010
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Pete Dartnell
Contact_Organization:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Contact_Position: Physical Scientist
Contact_Address:
Address_Type: mailing and physical address
Address: 400 Natural Bridges Dr.
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060-5792
Country: USA
Contact_Voice_Telephone: (831) 460-7415
Contact_Electronic_Mail_Address: pdartnell@usgs.gov

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell

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: 0.9996
Longitude_of_Central_Meridian: -123.00000
Latitude_of_Projection_Origin: 0.00000
False_Easting: 500000.0
False_Northing: 0.00
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 2.0
Ordinate_Resolution: 2.0
Planar_Distance_Units: Meters
Geodetic_Model:
Horizontal_Datum_Name: WGS84
Ellipsoid_Name: WGS84
Semi-major_Axis: 6378137.00 meters
Denominator_of_Flattening_Ratio: 298.257223563

Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
The merged CSUMB 2004, 2005, Mouth of San Francisco Bay, Reson 8101 backscatter data that was re-processed by the USGS in 2010 was originally archived as an ESRI grid with the following attributes: 
Cell size = 2.0
Number of rows = 8845
Number of columns = 8850
Data type = floating point
Boundary
Xmin = 533700
Xmax = 551400
Ymin = 4172360
Ymax = 4190050
Statistics
Minimum value = 2
Maximum value = 255
Mean = 152.87
Standard deviation = 24.94
Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
The 2007 Reson 8101 acoustic-backscatter grid was originally archived as an ESRI grid with the following attributes: 
Cell size = 2.0
Number of rows = 8845
Number of columns = 8850
Data type = floating point
Boundary
Xmin = 533700
Xmax = 551400
Ymin = 4172360
Ymax = 4190050
Statistics
Minimum value = 39
Maximum value = 254
Mean = 108.43
Standard deviation = 22.19
Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
The 2008 Reson 8101 acoustic-backscatter grid within San Francisco Bay was originally archived as an ESRI grid with the following attributes: 
Cell size = 2.0
Number of rows = 8845
Number of columns = 8850
Data type = floating point
Boundary
Xmin = 533700
Xmax = 551400
Ymin = 4172360
Ymax = 4190050
Statistics
Minimum value = 1
Maximum value = 254
Mean = 159.38
Standard deviation = 48.60
Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
The 2006 Reson 7125 acoustic-backscatter grid was originally archived as an ESRI grid with the following attributes: 
Cell size = 2.0
Number of rows = 8845
Number of columns = 8850
Data type = floating point
Boundary
Xmin = 533700
Xmax = 551400
Ymin = 4172360
Ymax = 4190050
Statistics
Minimum value = 2
Maximum value = 254
Mean = 154.52
Standard deviation = 25.03
Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
Entity_and_Attribute_Detail_Citation: none


Metadata_Reference_Information:
Metadata_Date: 20131022
Metadata_Review_Date: 20140829
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Peter Dartnell
Contact_Organization:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Contact_Position: Physical Scientist
Contact_Address:
Address_Type: mailing and physical address
Address: 400 Natural Bridges Dr.
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060-5792
Country: USA
Contact_Voice_Telephone: (831) 460-7415
Contact_Facsimile_Telephone: (831) 427-4709
Contact_Electronic_Mail_Address: pdartnell@usgs.gov
Metadata_Standard_Name:
Content Standard for Digital Geospatial Metadata ("CSDGM version 2")
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: universal time











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