BackscatterB [Swath]--Offshore of Point Reyes Map Map Area, California

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Janet T. Watt
Originator: Michael W. Manson
Originator: H. Gary Greene
Publication_Date: 2014
Title:
BackscatterB [Swath]--Offshore of Point Reyes Map Map Area, California
Geospatial_Data_Presentation_Form: raster digital data
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: http://pubs.usgs.gov/ds/781/
Description:
Abstract:
This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Point Reyes map area, California. Backscatter data are provided as separate grids depending on mapping system or processing method. The raster data files are included in "BackscatterB_Swath_PtReyes.zip", which are accessible from http://pubs.usgs.gov/ds/781/OffshorePointReyes/data_catalog_PointReyes.html
The acoustic-backscatter map of the Offshore of Point Reyes map area, California, was generated from backscatter data collected by California State University, Monterey Bay (CSUMB), and by Fugro Pelagos. Mapping was completed between 2007 and 2010, using a combination of 200-kHz and 400-kHz Reson 7125, and 244-kHz Reson 8101 multibeam echosounders, as well as 468-kHz SEA SWATHPlus interferometric system. These mapping missions combined to collect 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 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). NOTE: the horizontal datum of the backscatter data (NAD83) differs from the horizontal datum of other layers in this DS (WGS84). These data are not intended for navigational purposes.
Purpose:
To expand geologic mapping to the seafloor within the California's State Waters, to update coastal geologic mapping, and to contribute to a uniform regional geologic database, which can be used geographic information systems. Additionally, to provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the Point Reyes coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. This information is not intended for navigational purposes.
Supplemental_Information: None
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 2007
Ending_Date: 2010
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -123.09
East_Bounding_Coordinate: -122.89
North_Bounding_Coordinate: 38.10
South_Bounding_Coordinate: 37.94
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:196dd0eb-2f18-44d3-85a0-37a27368e989
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: ISO 19115 Topic Category
Theme_Keyword: geoscientificInformation
Theme_Keyword: environment
Theme_Keyword: oceans
Theme_Keyword: imageryBaseMapsEarthCover
Theme_Keyword: Multibeam bathymetry
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Benthic marine habitat
Theme_Keyword: Seafloor mapping
Theme_Keyword: Offshore geology
Theme_Keyword: GIS
Theme:
Theme_Keyword_Thesaurus: Data Categories for Marine Planning
Theme_Keyword: distributions
Theme_Keyword: physical habitats and geomorphology
Theme:
Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords
Theme_Keyword: seabed
Theme_Keyword: sidescan sonar
Theme_Keyword: marine geophysics
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: sidescan sonar
Theme_Keyword: image mosaics
Theme_Keyword: marine geophysics
Theme_Keyword: sea-floor characteristics
Theme_Keyword: sea-floor acoustic reflectivity
Theme:
Theme_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS)
Theme_Keyword: Marine Nearshore Subtidal
Theme_Keyword: Marine Offshore Subtidal
Theme_Keyword: Transform Continental Margin
Theme_Keyword: Continental/Island Shelf
Theme_Keyword: Rock Substrate
Theme_Keyword: Unconsolidated Mineral Substrate
Place:
Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: Pacific Ocean
Place_Keyword: State of California
Place_Keyword: Point Reyes
Place_Keyword: Drakes Bay
Place_Keyword: Marin County
Place_Keyword: Drakes Estero
Place:
Place_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS)
Place_Keyword: Northern California Ecoregion
Stratum:
Stratum_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS)
Stratum_Keyword: Substrate
Access_Constraints:
If physical samples or materials are available, constraints on their on-site access are described in "WR CMG Sample Distribution Policy" at URL: http://walrus.wr.usgs.gov/infobank/programs/html/main/sample-dist-policy.html
Use_Constraints:
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.
USGS-authored or produced data and information are in the public domain. Acknowledge the U.S. Geological Survey and California State University, Monterey Bay, Seafloor Mapping Lab in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.
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.
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: Browse_Graphic_File_Description:
Acoustic backscatter imagery of the Offshore of Point Reyes map area.
Browse_Graphic_File_Type: GIF Offshore of Point Reyes map area
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
Lineage:
Process_Step:
Process_Description:
During the Fugro Pelagos and CSUMB mapping missions, an Applanix Position and Motion Compensation System for Marine Vessels (POS/MV, 320, v4) was used to accurately position the vessels during data collection, and it also accounted for vessel's motion such as heave, pitch, and roll (position accuracy, +/-2 m; pitch, roll, and heading accuracy, +/-0.02; heave accuracy, +/-5%, 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. The multibeam backscatter data then were processed using Geocoder (Fugro Pelagos Modified Test Release 16) or Geocoder within Caris HIPS and SIPS. Within Geocoder, the backscatter intensities were radiometrically corrected (including despeckling and angle-varying gain adjustments), and the position of each acoustic sample was geometrically corrected for slant range. This processed imagery was stored as Georeferenced, Backscatter Rasters (GeoBARs). After GeoBARs were created for each line, they were mosaicked into 1-m or 2-m resolution images. Overlap between parallel lines was resolved using a priority table based on the distance of each sample from the ship track, with samples closest to- and furthest from- the ship track given the lowest priority. An anti-aliasing algorithm was also applied. The SWATHPlus backscatter data were processed using SXPTools v 2.0 (David Finlayson, USGS) and SEA Grid Processor v 3.02.19.0. SXPTools is a collection of command line programs that are used to enhance the quality of SEA SWATHplus interferometric sidescan sonar data. The programs are primarily focused on enhancing the backscatter quality, but there is some benefit to the bathymetry as well. The SXPTools sxpegn command was used to equalize the backscatter amplitude, and the sxpmagic command was used to help fill gaps and remove artifacts near nadir. After processing with SXPTools, lines were imported into Grid Processor and mosaicked into 1-m or 2-m resolution image georeferenced to UTM Zone 10 N, NAD_83(CORS96). The mosaic image for each survey block was exported as a GeoJpeg from Grid Processor and converted to GeoTiff using Adobe Photoshop or GIMP. In some cases memory limitations in Grid Processor required tiling a block mosaic into 2 or more sub-mosaics.
Process_Date: 2010
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- or 2-m resolution backscatter imagery within this map were downloaded from California State University, Monterey Bay, Seafloor Mapping Lab (http://seafloor.csumb.edu/SFMLwebDATA.htm) and converted to grids. 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. Grids were projected horizontally to WGS-84 using ESRI ArcTools.
Process_Date: 2012
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
Process_Step:
Process_Description:
Modified Distribution_Information section in metadata to facilitate data download.
Process_Date: 20171005
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Alan O. Allwardt
Contact_Position: Contractor -- Information Specialist
Contact_Address:
Address_Type: mailing and physical address
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Contact_Voice_Telephone: 831-460-7551
Contact_Facsimile_Telephone: 831-427-4748
Contact_Electronic_Mail_Address: aallwardt@usgs.gov
Process_Step:
Process_Description:
Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.
Process_Date: 20171005
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Alan O. Allwardt
Contact_Position: Contractor -- Information Specialist
Contact_Address:
Address_Type: mailing and physical address
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Contact_Voice_Telephone: 831-460-7551
Contact_Facsimile_Telephone: 831-427-4748
Contact_Electronic_Mail_Address: aallwardt@usgs.gov
Process_Step:
Process_Description:
Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata.
Process_Date: 20180426
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Alan O. Allwardt
Contact_Position: Contractor -- Information Specialist
Contact_Address:
Address_Type: mailing and physical address
Address: 2885 Mission Street
City: Santa Cruz
State_or_Province: CA
Postal_Code: 95060
Contact_Voice_Telephone: 831-460-7551
Contact_Facsimile_Telephone: 831-427-4748
Contact_Electronic_Mail_Address: aallwardt@usgs.gov
Process_Step:
Process_Description:
Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.
Process_Date: 20201019
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross
Contact_Position: Marine Geologist
Contact_Address:
Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@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 Reson 8101 acoustic-backscatter grid was originally archived as an ESRI grid with the following attributes:
Cell size = 2.0
Number of rows = 8871
Number of columns = 8871

Data type = unsigned integer

Boundary
Xmin = 491688
Xmax = 509430
Ymin = 4198998
Ymax = 4216740

Statistics
Minimum value = 1
Maximum value = 254
Mean = 130.98
Standard deviation = 32.50

Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
The merged Reson 7125 acoustic-backscatter grid was originally archived as an ESRI grid with the following attributes:
Cell size = 2.0
Number of rows = 8871
Number of columns = 8871

Data type = unsigned integer

Boundary
Xmin = 491688
Xmax = 509430
Ymin = 4198998
Ymax = 4216740

Statistics
Minimum value = 0
Maximum value = 254
Mean = 113.79
Standard deviation = 29.21

Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
The merged SWATHPlus acoustic-backscatter grid was originally archived as an ESRI grid with the following attributes:
Cell size = 2.0
Number of rows = 8871
Number of columns = 8871

Data type = unsigned integer

Boundary
Xmin = 491688
Xmax = 509430
Ymin = 4198998
Ymax = 4216740

Statistics
Minimum value = 1
Maximum value = 254
Mean = 130.48
Standard deviation = 27.55

Coordinate system description
Projection  UTM
Zone  10
Datum  WGS84
Units  meter
Entity_and_Attribute_Detail_Citation: none
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing and physical address
Address: 345 Middlefield Rd
City: Menlo Park
State_or_Province: CA
Postal_Code: 94025-3561
Country: USA
Contact_Voice_Telephone: (650) 329-4309
Distribution_Liability:
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: https://pubs.usgs.gov/ds/781/
Fees: none
Metadata_Reference_Information:
Metadata_Date: 20201019
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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