Estero Bay, California, Acoustic Backscatter (Field Activity ID: S-05-12-SC)

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator:

U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), Santa Cruz, CA.

Publication_Date: 2013

Title:

Estero Bay, California, Acoustic Backscatter (Field Activity ID: S-05-12-SC)

Geospatial_Data_Presentation_Form: raster digital data

Series_Information:

Series_Name: U.S. Geological Survey Open-File Report

Issue_Identification: 2013-1225

Online_Linkage: <http://pubs.usgs.gov/of/2013/1225/>

Description:

Abstract:

Between July 30 and August 09, 2012, scientists from the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), acquired bathymetry and acoustic-backscatter data from Estero Bay, San Luis Obispo, California, under PCMSC Field Activity ID S-05-12-SC. The survey was conducted using the R/V Parke Snavely outfitted with a multibeam sonar system for swath mapping and inertially-aided real-time kinematic navigation equipment for accurate georeferencing. This report provides these data in a number of different formats, as well as a summary of the mapping mission, maps of bathymetry and backscatter, and Federal Geographic Data Committee (FGDC) metadata.

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 to identify bathymetric features. This information is not intended for navigational purposes.

Supplemental_Information:

The URL for USGS field activity S-05-12-SC is <http://walrus.wr.usgs.gov/infobank/s/s0512sc/html/s-05-12-sc.meta.html>

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20120730

Ending_Date: 20120809

Currentness_Reference: ground condition

Status:

Progress: complete

Maintenance_and_Update_Frequency: as needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -121.172404

East_Bounding_Coordinate: -120.915074

North_Bounding_Coordinate: 35.520167

South_Bounding_Coordinate: 35.224352

Keywords:

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category

Theme_Keyword: geoscientificInformation

Theme_Keyword: oceans

Theme_Keyword: elevation

Place:

Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)

Place_Keyword: State of California

Place_Keyword: San Luis Obispo

Place_Keyword: Estero bay

Place_Keyword: Morro Bay

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 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_Organization_Primary:

Contact_Organization: USGS Pacific Coastal and Marine Science Center

Contact_Person: Steve R Hartwell

Contact_Position: Geologist

Contact_Address:

Address_Type: physical address

Address: U.S. Geological Survey

Address: 400 Natural Bridges Drive

City: Santa Cruz

State_or_Province: CA

Postal_Code: 95060

Country: USA

Contact_Voice_Telephone: (831) 460-7814

Contact_Facsimile_Telephone: (831) 427-4748

Contact_Electronic_Mail_Address: shartwell@usgs.gov

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

This bathymetric data has not been independently verified for accuracy.

Logical_Consistency_Report:

All bathymetric values are derived from the same instruments and processing workflow.

Completeness_Report:

The 2012 mapping mission (U.S. Geological Survey (USGS) Field Activity ID: S-05-12-SC) collected high-resolution bathymetry and coregistered acoustic backscatter of outer Estero Bay, California. The survey was completed in 11 days, from July 30 to August 9, 2012, and consisted of 117 survey lines covering approximately 165 sq km in elevations ranging from about -45 m to -250 m relative to NAVD88. The survey extends from an existing bathymetric survey to approximately 15 km offshore with complete coverage within the area of interest.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Uncertainty in the horizontal position of each sounding is a function of the total uncertainty propagated through each of the following component instruments: 1) vessel GPS, 2) intertial motion unit (IMU), 3) water sound velocity model, and 4) beam spreading in the water column. Assuming no systematic errors in the measurement instruments themselves, beam spreading is the dominate source of positional uncertainty. The 1.5-degree sonar beam of the SeaBat 7111 results in horizontal uncertainty ranging from 0.15 m at 10 m slant range, to about 0.70 m at 50 m slant range.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

After filtering the data to remove obvious outliers, the standard deviation of the remaining sounding elevations was calculated for each 2 m x 2 m and 4 m x 4 m cell (each containing an average of 5 soundings for each 2 m cell, and 12 soundings for each 4 m cell) in CARIS. The mean standard deviation for all cells in the Estero Bay survey is 0.12 m, and 95 percent of the cells in the data set have a standard deviation of less than 0.30 m.

Lineage:

Process_Step:

Process_Description:

Sonar Data Collection
Bathymetric surveys were completed using a RESON SeaBat 7111 multibeam echosounder. The sonar was pole-mounted on the 34-foot USGS mapping vessel R/V Parke Snavely. GNSS position and inertial motion and orientation measurement data were recorded using an Applanix Position and Orientation Solutions for Marine Vessels (POS MV) 320 inertial-aided position and orientation system. The sonar head, GNSS antennae, and the inertial motion unit (IMU) were surveyed in place to a common reference frame with a Geodimeter 640 Total Station. The R/V Parke Snavely was outfitted with three networked workstations and a navigation computer for use by the captain and survey crew for data collection and initial processing.

Process_Date: 20120730

Process_Step:

Process_Description:

Geodetic Control
Geodetic control for the survey was established using the IN-Fusion SmartBase feature in the Applanix Position and Orientation System Post-Processing Package Mobile Mapping Suite (POSPac MMS, Version 6.1.4553.15282). IN-Fusion SmartBase is a feature in POSPac MMS that provides inertially-aided, carrier phase differential GNSS for mobile mapping platforms without requiring dedicated base receivers (Applanix, 2012). Instead, the software automatically selects a network of permanent GNSS reference stations accessible through the Internet and provides reference receiver coverage over the entire project area. The network of reference stations selected by the software changed slightly each day depending on the exact location of the survey vessel and the quality of the reference station data for the selected day.

Process_Date: 20120809

Process_Step:

Process_Description:

Vessel Position and Attitude
The R/V Parke Snavely was equipped with a POS MV 320 system, which records inertial-motion and GNSS position data for the duration of the survey. The POS MV provides real-time pitch information to the multibeam sonar system to facilitate pitch-compensation (see discussion below). As discussed in the Geodetic Control Section, the GNSS data are combined with the inertial-motion measurements within the POSPac MMS software and high-precision position and attitude corrections are exported as SBET files for merging with the multibeam data.

Process_Date: 20120809

Process_Step:

Process_Description:

Sound Velocity Measurements
Sound velocity measurements were collected continuously with an Applied Micro Systems Micro SV deployed on the transducer frame for real-time sound velocity adjustments at the transducer-water interface. The Micro SV is accurate to 0.03 m/s. In addition, sound velocity profiles (SVP) were collected with an Applied Micro Systems, SvPlus 3472. This instrument provided time-of-flight sound-velocity measurements by using invar rods with a sound-velocity accuracy of +/- 0.06 m/s, pressure was measured by a semiconductor bridge strain gauge to an accuracy of 0.15 percent (500 dbar, full scale), and temperature was measured by thermistor with an accuracy of 0.05 degrees Celsius.

Process_Date: 20120809

Process_Step:

Process_Description:

Sonar Sounding Processing
CARIS HIPS and SIPS (version 7.1.0) bathymetry processing software was used to georeference the raw sonar data. The real-time attitude and position data was replaced with processed SBET data (described above); sound velocity corrections were applied; and the Total Propagated Uncertainty (TPU) for each sounding was estimated using Caris tools.

Process_Date: 20120809

Process_Step:

Process_Description:

Backscatter Image Production
Acoustic backscatter data were processed using Fledermaus (QPS) FMGeocoder software package (version 7.3.2). Survey line bathymetry data were exported from the Caris HIPS and SIPS (version 7.1) acquisition software as GSF files. These line files were paired with the original backscatter lines files (s7K) and imported into the FMGeocoder software. Each line file was radiometrically corrected and adjusted for Angle Varying Gain (AVG) with the “Flat” option with a window size of 30. All processed line files were merged together into one overall 2-m resolution backscatter mosaic. The processed backscatter dB values for a number of lines were adjusted using the backscatter adjustment tool to better match surrounding backscatter dB values. This tool allows the user to manually adjust dB values over entire lines. Often, the dB values within a line changed abruptly causing the mosaic to look “patchy.” Due to this manual adjustment process and abrupt changes in dB values, the backscatter mosaic may be more useful for visual interpretations rather than empirical characterizations that compare pixel values over the entire mosaic. Once finalized, the backscatter mosaic was exported as a geoTIFF, imported in ESRI ArcGIS and converted to a grid.

Process_Date: 20130218

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: raster

Raster_Object_Information:

Raster_Object_Type: grid cell

Row_Count: 16020

Column_Count: 11456

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

Latitude_of_Projection_Origin: 0.0

False_Easting: 500000

False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row and column

Coordinate_Representation:

Abscissa_Resolution: 2.0

Ordinate_Resolution: 2.0

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: World Geodetic System 1984 (G1150)

Ellipsoid_Name: WGS 84

Semi-major_Axis: 6378137

Denominator_of_Flattening_Ratio: 298.257

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: World Geodetic System 1984 (G1150)

Altitude_Resolution: 0.01

Altitude_Distance_Units: meters

Altitude_Encoding_Method: Attribute values

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: Acoustic Bacscatter Amplitude

Entity_Type_Definition:

Acoustic backscatter shows the relative strength of the acoustic signal returned from the seafloor.

Entity_Type_Definition_Source: USGS

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

U.S. Geological Survey, Pacific Coastal and Marine Science Center (PCMSC)

Contact_Person: Steve Hartwell

Contact_Address:

Address_Type: mailing and physical address

Address: U.S. Geological Survey

Address: 400 Natural Bridges Drive

City: Santa Cruz

State_or_Province: CA

Postal_Code: 95060-5792

Country: US

Contact_Voice_Telephone: (831) 460-7814

Contact_Facsimile_Telephone: (831) 427-4748

Contact_Electronic_Mail_Address: shartwell@usgs.gov

Resource_Description: Downloadable Data

Distribution_Liability:

This information is not intended for navigational purposes.
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.
Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: ESRI ASCII Grid

Format_Version_Number: 1.0

Format_Information_Content:

The ASCII file consists of header information containing a set of keywords, followed by cell values in row-major order. The file format is:

<NCOLS xxx>
<NROWS xxx>
<XLLCENTER xxx | XLLCORNER xxx>
<YLLCENTER xxx | YLLCORNER xxx>
<CELLSIZE xxx>
{NODATA_VALUE xxx}
row 1
row 2
.
.
.
row n

where xxx is a number, and the keyword nodata_value is optional and defaults to -9999. Row 1 of the data is at the top of the grid, row 2 is just under row 1 and so on. The nodata_value is the value in the ASCII file to be assigned to those cells whose true value is unknown. In the grid they will be assigned the keyword NODATA. Cell values are be delimited by spaces. No carriage returns are necessary at the end of each row in the grid (although they are included in this case). The number of columns in the header is used to determine when a new row begins. The number of cell values is equal to the number of rows times the number of columns.

Transfer_Size: 685 MB

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://pubs.usgs.gov/of/2013/1225/>

Fees: No cost

Metadata_Reference_Information:

Metadata_Date: 20130129

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

Pacific Coastal and Marine Science Center (PCMSC), US Geological Survey

Contact_Address:

Address_Type: mailing address

Address: U.S. Geological Survey

Address: 400 Natural Bridges Drive

City: Santa Cruz

State_or_Province: California

Postal_Code: 95060

Country: USA

Contact_Voice_Telephone: (831) 460-7814

Contact_Electronic_Mail_Address: shartwell@usgs.gov

Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998