Backscatter B [USGS]--Offshore of Ventura, California

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Peter Dartnell
Originator: Rikk G. Kvitek
Originator: Eleyne L. Phillips
Originator: Guy R. Cochrane
Publication_Date: 2013
Title: Backscatter B [USGS]--Offshore of Ventura, California
Edition: 1.0
Geospatial_Data_Presentation_Form: GeoTiff
Larger_Work_Citation:
Citation_Information:
Originator: Samuel Y. Johnson
Originator: Peter Dartnell
Originator: Guy R. Cochrane
Originator: Nadine E. Golden
Originator: Eleyne L. Phillips
Originator: Andrew C. Ritchie
Originator: Rikk G. Kvitek
Originator: H. Gary Greene
Originator: Lisa M. Krigsman
Originator: Charles A. Endris
Originator: Gordon G. Seitz
Originator: Carlos I. Gutierrez
Originator: Ray W. Sliter
Originator: Mercedes D. Erdey
Originator: Florence L. Wong
Originator: Mary M. Yoklavich
Originator: Amy E. Draut
Originator: Patrick E. Hart
Originator: Susan A. Cochran
Publication_Date: 2013
Title:
California State Waters Map Series--Offshore of Ventura, California
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: Scientific Investigations Map
Issue_Identification: SIM 3254
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: <https://pubs.usgs.gov/sim/3254/>
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 SIM 3254 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3254) of the Offshore Ventura map area, California. The raster data file is included in "BackscatterB_USGS_OffshoreVentura.zip," which is accessible from <https://pubs.usgs.gov/ds/781/OffshoreVentura/data_catalog_OffshoreVentura.html>. The acoustic-backscatter map of the Offshore Ventura map area, California, was generated from backscatter data collected by California State University, Monterey Bay, Seafloor Mapping Lab (CSUMB) and by the U.S. Geological Survey (USGS). These metadata describes the acoustic-backscatter data collected by the USGS (see "BackscatterA_CSUMB_OffshoreVentura_metadata.txt" metadata for a description of the acoustic-backscatter data collected by CSUMB). The seafloor west of Ventura Harbor was mapped by the USGS in 2006 and 2010, using 117-kHz (2006) and 234.5-kHz (2010) SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonars. These mapping missions collected acoustic-backscatter data from about the 10-m isobath to beyond the 3-nautical-mile limit of California's State Waters. Within the acoustic-backscatter 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 sediment type. 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.
Supplemental_Information:
Information for the related USGS Pacific Coastal and Marine Science Center data collection field activities, Z-2-06-SC online at <http://walrus.wr.usgs.gov/infobank/z/z206sc/html/z-2-06-sc.meta.html> and S-W1-09-SC online at <http://walrus.wr.usgs.gov/infobank/s/sw109sc/html/s-w1-09-sc.meta.html>.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 2006
Ending_Date: 2010
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -119.44
East_Bounding_Coordinate: -119.25
North_Bounding_Coordinate: 34.38
South_Bounding_Coordinate: 34.22
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: Santa Barbara Channel
Place_Keyword: Ventura
Place_Keyword: Ventura Harbor
Place_Keyword: Pacific Ocean
Place_Keyword: 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 USGS and CSUMB 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
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 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
Lineage:
Process_Step:
Process_Description:
USGS acoustic-backscatter data were collected in 2006 and 2010, using 117-kHz (2006) and 234.5-kHz (2010) SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonars aboard the USGS R/V Parke Snavely. The survey vessel was equipped with a CodaOctopus F180 attitude and position system. This system combines differential GPS data (2006) and real time kinematic GPS data (2-centimeter error ellipse) (2010) with inertial motion measurements so that high-precision position and attitude corrections are fed in real-time to the sonar acquisition equipment. Up to 10 pings per second are transmitted, each ping consisting of 2,048 samples per side (port and starboard). The returned samples are projected to the seafloor using a ray-tracing algorithm working with the previously measured sound-velocity profiles. A series of statistical filters are applied to the raw samples that discriminate the seafloor returns from other unintended targets in the water column. The raw 16-bit backscatter data recorded simultaneously with bathymetry by the SWATHplus was georeferenced and gain-normalized by the program SXPEGN, software written by the USGS to enhance the backscatter of the SWATHplus system. The program normalizes for time-varying signal loss and beam-directivity differences. The resulting normalized-amplitude values are rescaled to 16-bit and gridded into a GeoJPEG image using GRID Processor Software supplied by SEA. The GeoJPEG was imported into a GRID using ESRI GIS software and clipped to the Offshore of Ventura map area boundary.
Process_Date: 2011
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: 11
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: -117.00000
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 USGS 2006 backscatter grid was originally archived as an ESRI grid with the following attributes: 
Cell size = 2.0
Number of rows = 3623
Number of columns = 3643

Data type = floating point

Boundary
Xmin = 284123.00
Xmax = 291409.00
Ymin = 3787799.00
Ymax = 3795045.00

Statistics
Minimum value = 0
Maximum value = 255
Mean = 194.32
Standard deviation = 62.68

Coordinate system description
Projection  UTM
Zone  11
Datum  WGS84
Units  meter
The USGS 2010 backscatter grid was originally archived as an ESRI grid with the following attributes: 
Cell size = 2.0
Number of rows = 3235
Number of columns = 1995

Data type = floating point

Boundary
Xmin = 283431.00
Xmax = 287421.00
Ymin = 3784973.00
Ymax = 3791443.00

Statistics
Minimum value = 0
Maximum value = 254
Mean = 118.11
Standard deviation = 33.31

Coordinate system description
Projection  UTM
Zone  11
Datum  WGS84
Units  meter
Entity_and_Attribute_Detail_Citation: none
Metadata_Reference_Information:
Metadata_Date: 20130315
Metadata_Review_Date: 20130315
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

Generated by mp version 2.9.6 on Tue Jul 09 17:32:27 2013