Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), Santa Cruz, CA. Publication_Date: 2011 Title: Ediz Hook (Outside), Port Angeles Harbor, Washington, Acoustic Backscatter (Cruise ID: S-6-10-PS) Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 1226 Online_Linkage: http://pubs.usgs.gov/of/2011/1226/ Description: Abstract: Between February 22, 2010 and March 3, 2010 the U.S. Geological Survey, Pacific Coastal and Marine Science Center mapped the bathymetry and acoustic backscatter of the Elwha River Delta, Strait of Juan de Fuca, Washington State. In addition to the main survey, 3 small surveys of interest to USGS partners were conducted on February 26, 2010. The first is the area surrounding the abandoned Rayonier Pier site in Port Angeles Harbor, the second is a former log-storage facility on the southern side of Ediz Hook near the Port Angeles Coast Guard station. Both of these smaller surveys were conducted during a weather day where sea conditions were too rough for surveying outside the harbor breakwaters. In addition, several lines of data were collected on the outer face of Ediz hook as the vessel transited to and from the Elwha river delta to inspect failure features along the northen edge of Ediz Hook first observed in 2005 during USGS cruise K-1-05-PS. The surveys were conducted using the research vessel R/V Parke Snavely outfitted with an interferometric sidescan sonar for swath mapping and Real-Time Kinematic navigation equipment for accurate shallow water operations. Purpose: Inspect failure features along the northen edge of Ediz Hook first observed in 2005 during USGS cruise K-1-05-PS. Supplemental_Information: The URL for USGS field activity S-6-10-PS is The URL for USGS field activity K-1-05-PS is Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100222 Ending_Date: 20100303 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: as needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -123.469751 East_Bounding_Coordinate: -123.401175 North_Bounding_Coordinate: 48.146454 South_Bounding_Coordinate: 48.136109 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificinformation Theme_Keyword: oceans Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: USA Place_Keyword: State of Washington Place_Keyword: Strait of Juan de Fuca Place_Keyword: Port Angeles Harbor Place_Keyword: Ediz Hook 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: Not suitable for navigation. Read and fully comprehend the metadata prior to data use. Acknowledge the U.S. Geological Survey (USGS), the Originator, when using the data set as a source. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Share data products developed using the source data set with the Originator. Data should not be used beyond the limits of the source scale. This information is not intended for navigational purposes. The data set is NOT a survey document and should not be utilized as such. Some USGS information accessed through this means may be preliminary in nature and presented without the approval of the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the responsibility of the user. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Pacific Coastal and Marine Science Center Contact_Person: David P Finlayson 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) 427-4757 Contact_Facsimile_Telephone: (831) 427-4748 Contact_Electronic_Mail_Address: dfinlayson@usgs.gov Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: This bathymetric data has not been independently verified for accuracy. Logical_Consistency_Report: All acoustic backscatter values are derived from the same instruments and processing workflow. Normalized acoustic backscatter shows the relative strength of the acoustic signal returned from the seafloor. The normalization process compensates for acoustic signal strength differences due to time varying gain (TVG), spreading and many static sonar artifacts (those that repeat from ping-to-ping). The values are comparable across the entire dataset regaurdless of water depth or distance and angle from the transducer. Completeness_Report: These data consist of 4 survey lines collected as time allowed during transites to and from the main survey area to the west near the Elwha River. The first line extends along much of the north side of Ediz Hook and was used to identify the top of slump features first identified during USGS cruise K-1-05-PS. The remaining 3 lines were used to fill in as much detail as possible over the slump features. At the base of the spit (around 60 m depth) there is a data gap, otherwise most of the area of interest was ensonified. 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) base station GPS, 2) vessel GPS, 3) intertial motion unit (IMU), 4) water sound velocity model, and 5) 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-degree sonar beam of the SWATHplus-M results in horizontal uncertainty ranging from 0.10 m at 10 m slant range, to about 0.45 m at 50 m slant range. Lineage: Process_Step: Process_Description: Sonar Data Collection The bathymetric surveys were conducted using a 234.5 kHz SEA (Systems Engineering & Assessment Ltd) SWATHplus-M phase-differencing sidescan sonar. The sonar was pole-mounted on the 34-foot USGS mapping vessel R/V Parke Snavely, and affixed to a hull brace. Real-time kinematic (RTK) GPS position data were passed through a CodaOctopus F180 intertial measurement unit (IMU) to the sonar hardware and data collection software. Sonar heads, GPS antennae, and the IMU were surveyed in place to a common reference frame with a Geodimeter 640 Total Station. The R/V 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: 20100222 Process_Step: Process_Description: Geodetic Control Geodetic control for the survey was established using a shore based Global Positioning System (GPS) base station broadcasting Real Time Kinematic (RTK) corrections to the survey vessel via UHF radio link. The base station was located at the base of Ediz Hook. The base station was programmed using the WGS84 (G1150) reference frame with an Epoch of 2010.1548. Average Opus Solution coordinates for the station are: Reference Frame: WGS84 (G1150) Epoch: 2010.1548 Latitude: N 48° 08 06.01943 Longitude: W 123° 28 06.90674 Ellipsoid Height: -11.355m The average values for the derived OPUS solution for MILL are: Reference Frame: ITRF00 [same as WGS84 (G1150)] Epoch: 2010.1548 Latitude: N 48° 08 06.01936 Longitude: W 123° 28 06.90685 Ellipsoid Height: -11.351m The differences to be added to the RTK broadcast locations are: Latitude: -0.00007 Longitude: +0.00011 Ellipsoid Height: +0.004m Using UTM coordinates as a comparison: The base station was programmed using the following coordinates: Reference Frame: NAD83, UTM zone 10 Epoch: 2002.0000 Northing: 5331411.376m Easting: 465138.251m Ellipsoid Height: -11.042m Orthometric Height: 9.155m (based Geoid09) Process_Date: 20100222 Process_Step: Process_Description: Vessel Position and Attitude The R/V Snavely was equipped with a CodaOctopus F180 attitude and positioning system for the duration of the survey. The F180 is running F190 firmware, and receives real-time kinematic (RTK) corrections directly. The RTK GPS data (2 cm error ellipse) are combined with the inertial motion measurements directly within the F190 hardware so that high-precision position and attitude corrections are fed in real-time to the sonar acquisition equipment. The WGS84 (G1150) Epoch 2010.1548 3-dimensional reference frame was used for all data acquisition. Process_Date: 20100222 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 provides time-of-flight sound-velocity measurements by using invar rods with a sound-velocity accuracy of ±0.06 m/s, pressure measured by a semiconductor bridge strain gauge to an accuracy of 0.15 percent (Full Scale) and temperature measured by thermistor to an accuracy of 0.05 degrees Celsius (Applied Microsystems Ltd., 2005). Process_Date: 2010022 Process_Step: Process_Description: Sonar Sounding Processing GPS data and measurements of vessel motion are combined in the F180 hardware to produce a high-precision vessel attitude packet. This packet is transmitted to the Swath Processor acquisition software in real-time and combined with instantaneous sound velocity measurements at the transducer head before each ping. Up to 20 pings per second are transmitted with each ping consisting of 2048 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 in SEA Swath Processor (version 3.05.18.04). A series of statistical filters are applied to the raw samples that isolate the seafloor returns from other uninteresting targets in the water column. Finally, the processed data is stored line-by-line in both raw (.sxr) and processed (.sxp) trackline files. Processed (.sxp) files were further processed with sxpegn (build 151) by David Finlayson (USGS) to remove erroneous data from the files and make valid gain-normalized amplitude data for processing backscatter data. Process_Date: 2010022 Process_Step: Process_Description: Backscatter Image Production The raw 16-bit backscatter recorded simultaneously with the bathymetry by the SWATHplus was georefrenced and gain-normalized by the program SXPEGN, software purpose 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 re-scaled to 16-bit, binned at 1m resolution in SEA Grid Processor and exported as point files. The binned points are gridded using Surfer with an inverse distance weighted algorithm using a 3 m search radius and a 0.25 m smoothing parameter. The data were exported from Surfer in ESRI ASCII Grid format. Process_Date: 20110412 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: raster Raster_Object_Information: Raster_Object_Type: grid cell Row_Count: 1122 Column_Count: 5109 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: 1.0 Ordinate_Resolution: 1.0 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 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Normalized Acoustic Bacscatter Amplitude Entity_Type_Definition: The raw 16-bit backscatter recorded simultaneously with the bathymetry by the SWATHplus was georefrenced and gain-normalized by the program SXPEGN, software purpose 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 re-scaled to 16-bit, exported as point files and gridded into GeoJPEGS using GRID Processor Software supplied by SEA. Normalized acoustic backscatter shows the relative strength of the acoustic signal returned from the seafloor. The normalization process compensates for acoustic signal strength differences due to time varying gain (TVG), spreading and many static sonar artifacts (those that repeat from ping-to-ping). The values are comparable across the entire dataset regaurdless of water depth or distance and angle from the transducer. Low normalized acoustic backscatter values indicate relatively low acoustic target signal strength; High normalized acoustic backscatter values indicate relatively high acoustic target signal strength. 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: David P Finlayson 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: 831-427-4757 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: dfinlayson@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: This information is not intended for navigational purposes. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Physical materials are under controlled on-site access. Some USGS information accessed through this means may be preliminary in nature and presented without the approval of the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the responsibility of the user. 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: > > > > > > >{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: 381 MB Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2011/1226/ Fees: No cost Metadata_Reference_Information: Metadata_Date: 20110411 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: 8314274757 Contact_Electronic_Mail_Address: dfinlayson@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998